Italy Itinerary advice/tweaks/input?

You have a pretty good plan already.

I will try to assist.

First, I think you are right to stick to Venice and Rome for a 9 day trip.

Second, we have been to Venice 4 or 5 times and love the city. Biggest hassle is going from the highway system to a city where the "roads" are canals and transport is by boat.

When we stayed in Venice, we went with budget accommodations in a cheaper part of the city (near the main train station).
We took the bus for 5 Euros (It think it is a little more today) into the Pizzale Roma that is just across a canal from the main train station.
We then walked to our hotel, dragging our luggage.
https://www.introducingvenice.com/map/piazzale-roma

You can't do that, since your B&B is near the Rialto. You could take the Vaporetto, a kind of bus line on the Grand Canal. A single journey ticket will cost 7 Euros.
https://www.introducingvenice.com/water-bus

Or, you could take a water taxi.
https://www.introducingvenice.com/water-taxis
Water taxi will cost at least 100 Euros, probably more.

Take a look at the map on the Vaporetto link and see if that works for getting to your hotel. Also, if you have more luggage than a checked suitcase and a small carryon, you might not want to schlep you luggage on to the Vaporetto. We did it and we were in our early 60s.

2nd response

I don't have much to say about the Rome portion of your trip. You probably want to do a taxi for the 0600 tour. Your B&B can arrange.

I am not a big fan of those day trips from Rome to Pompeii. There is a lot more to see in the Naples area than Pompeii. I suggest saving that visit for another trip to Italy. If you haven't been to Florence, you should consider visiting there as well.
That day trip will be tiring and involve lots of travel.

There is a lot more to see in Rome that you haven't planned for, so you could plug into something more in Rome.
The day you do the Colosseum, you will have a large part of the day to visit the Roman Forum and Palatine Hill. I suggest you do that.
Also, you could go to the Capitoline Museum, which is on the ancient Capitoline Hill where the original temple to Jupiter was located.
You should try to visit the Spanish Steps, Piazza Navona and the Pantheon. If you can squeeze in visiting Trajan's Forum that would be great.

There is more to see in Rome, but I probably gave you plenty. I love Rome and its ancient history, it is one of my favorite cities. Just watch for pickpockets, especially if you take the subway.

Any possibility of switching the Colosseum and Catacombs tours? It is best of see the catacombs on a Sunday since the traffic on the Appian Way is substantially reduced. Otherwise it is just another traffic filled street in Rome and almost no room for walking.

The metro in Rome is fairly limited in where it goes. Basically two fingers that cross in Termini. The metro stop Barberini is a couple of blocks from the Plazza B. There is a metro stop Colosseo right at the Colosseum. Not familiar with Plazza Ostiense. You might give this a try ---- https://moovitapp.com/index/en/public_transit-Piazzale_Ostiense-Roma_e_Lazio-site_14803206-61

The best way from hotel to airport would be a taxi -- fixed price of 48 euro.

You will love Italy in October! Still crowded but nowhere near as crowded as the summer ... and a lot cooler!

In Venice, we bought the ACTV 72 hour vaporetto pass and airport transfer and it was very easy to get to our hotel. You can buy a pass or tickets at the airport. We bought ours online ahead of time (so I could have it paid for), went to the ACTV machine outside the terminal and entered a code for our passes. We took the #5 Airport Shuttle Bus right outside the airport terminal to the end and we only had a very short walk to the vaporetto stop (can't miss it). It goes down the Grand Canal to the Rialto Bridge. A wonderful way to see Venice! Hopefully, you can leave your luggage at your AirBnB early. With the vaporetto pass, we were able to hop on and off the vaporetto whenever we wanted. We would just hop on and see where we ended up. We went to Murano, ended up on an island that was a cemetery (and very interesting) and took evening rides down the canal and just enjoyed the sights! The vaporetto also went right to the train station. Just make sure to validate your ticket each time.

Another thing we did in Venice was a food and wine tour with Savor Italy Food Tours! What a great way to start our trip! We met people from England, Australia and Florida! So much fun and we went to places we never would have found in our own! I'm pretty sure our meeting point was near the Rialto Bridge.
You might also want to check out the rooftop terrace at T Fondaco dei Tedeschi by DFS. You can make a reservation there or online 15 days in advance to go up on their rooftop for FREE and see Venice! Beautiful views and right by the Rialto Bridge! https://www.dfs.com/en/venice/t-fondaco-rooftop-terrace.

Have a great time! I think Venice is one of the most beautiful, magical cities I've ever visited!

I only have a couple things to add. From Marco Polo airport to your hotel in Venice you have 3 options. The first is the water taxi that you will find at the docks at the airport ( You will see signs. Keep veering left. It is a hike from the gates.) It is the most expensive---- about 100 Euros last May-- but you could share the cost with others. The next option is also at the docks. The Aliliguna boats. One way is about 15 Euros. The Orange line takes you to the Rialto stop. We took this option and were disappointed with the experience. It was a long wait for a boat; we were down inside the boat at almost the water level trying to see the wonder of entering Venice through filthy windows. The l3adt option is a bus. These take you to Piazzale Roma where you then must take a vaporetto to your stop. To my mind it would have been worth the expense to use the water taxi.

When we were in Rome and needing transportation from our B and B to the airport, we hired Romecabs ahead of time online. I can't say enough about how professional the driver was. On time and in a Mercedes! You book ahead but pay the day of your transfer. I would not hesitate to recommend this company. You can check them out online.

This website will be your friend:
www.rome2rio.com

Enter any two locations, and it gives you the bus, vsporetto, train, walking, etc. options . Pick your transportation option from the left column, and the map updates with the route and bus stop names, for instance. I find it very handy to see the local transportation link to the transportation website and also how to walk to our hotel from a bus stop. Just be sure to verify the actual total time to travel because some of those can be less accurate.

You also cannot trust the fares or frequencies shown by Rome2Rio. Just use the links it provides to go to the website of the company operating the transportation you need.

Just what do you mean by "so many people!" ???

Thank you all for the input! We dont usually do alot of the tours but this time around were are trying to take things slow because we found out that I will be 5 months pregnant while we are in Italy, with our first!
My husband's photography hobby will keep us busy for the down time, but I definitely will check out some of the places you guys have listed.

Thank you!!!!

Also have any of you used to 7 day transit pass? We are usually very active when traveling, I'm just not sure how I will be fairing and would like the option to ride instead of walk if needed.

I would skip the Pompeii trip if you will be pregnant. It is a grueling day without being pregnant.

I second what Joyce said:

We took the no. 5 bus from Marco Polo. I purchased online and entered the reservation code in the ticket machine at the airport and the bus stop is right there. Marco Polo is a small airport. Bus drops off at Piazzale Roma and the Vaporetti are right there. We also bought the 3 day pass. Easy. Just remember to validate on first use.

https://getbybus.com/en/blog/venice-airport-bus/

We had 3 great days in Venice. Try to get to the Frari church. RS has a audio tour of church (as well as one for a vaporetto ride down the grand canal)
When leaving Venice, just take the vaporetto to Santa Lucia Station. it's not huge and will be easy to figure out which track (binari). Look at signs for Partenze (departures) for Roma. If you're early your train may not be there yet. If you have not purchased, I would buy your tickets to Rome Termini ASAP. The price goes up the longer you wait. Be sure to pick the non stop, to Roma TERMINI. It should be on the high speed Frecciarossa (red arrow). Get the reservation code delivered to mail/phone and just show conductor your barcode. i can't remember if we had assigned seats.
https://us.trenitalia.it-inter.com/

Once in Rome: be careful at Termini Station, Lot of characters. Same with Spanish Steps. Take the Metro line B to the Colosseo stop and walk from there. There may be a phone app for the Rome metro. Try to stick to metro as opposed to buses if you can.

Some other things in Rome: The Cappucin Crypts http://www.cappucciniviaveneto.it/

Campo Dei Fiori has a great market for shopping for goodies for your airbnb or some street food.
https://www.eatingeurope.com/blog/campo-dei-fiori-food-market/

St. Peters: Be sure to visit the crypts underneath the Basilica. It's accessed via a doorway in the church. Ask one of the guards. It's the resting place of several of the Popes and other noteworthy people. When I was there, Pope John Paul II was there, but not sure anymore. He may have been moved. There is Gregorian Chant music playing to set the mood.

You may want to check out Viator for various day or half day tours in Rome or day trips from Rome if you think you'll have spare time.

See if the Venice check-in time is really firm --- about half the time, we find that the host can accommodate us with an earlier check-in if asked nicely. If it is firm, see if you can at least leave your luggage in the apartment.

The Ostiense train station in Rome is next to the Piramide Metro station AND to the Porta San Paolo train station which has the Rome–Lido commuter line to Ostia Antica. Ostia Antica is different from Pompeii but so much easier and quicker to get to from Rome. Also much, much less crowded. Look at some photos and see what you think.

If you get the vaporetto pass in Venice, remember to validate every time you use it. There is a small machine at each stop and you just need to scan it before entering. You can be fined if you are caught not validating.

Great plan for a short trip! I would get the 72 hour pass and use the vaporetto for getting around Venice. It's so convenient. Buy the pass at the airport and take the bus. The vaporetto will take you everywhere...Burano (or Murano), wherever...
In Rome for the early travel the taxis are your best bet. Make reservations in advance and relish the convenience. It's worth the cost.
Pompeii...save that for a trip with a focus on the South. Fly to Naples....there are lot's of Rome sites that will be easier for you to enjoy.