Hi I m gonna travel in Europe.

Is 9 days the extent of your trip, or do you have other time planned for Europe?

From Bavaria, you can certainly do day trips, but it likely will just be the local area, perhaps into Austria, Frankfurt would be possible, but Paris and Zurich as day trips are not practical. Zurich would be an expensive stop, Paris not much cheaper, if you decide to spend additional nights places, consider getting an apartment, better for a large group.

For transportation, a Lander-Ticket, a day pass, (see details here: https://www.bahn.com/en/view/offers/regional/regional-day-tickets.shtml ) would be the cheapest route, it would cover nearly all transport in Bavaria, is valid for up to 5 people, you may need to investigate what would be required for the children, depending on their ages.

As for travel overnight, the days of Night sleeper trains are fast disappearing, I doubt that you would find any that work for you.

You really should read some travel books in order to better decide where you want to travel.
I agree about seeing Paris, but most travelers prefer to go other place than Zurich and Frankfort. They're not in the most scenic of places. And Bavaria is a large place--as you need to say where in the region you wish to stay.
It's not good for 5 people to travel at night to avoid having to pay for a hotel. If you're on that much of a budget, you may need to allocate more money for your trip--or go to Europe when you have the financial resources to travel in a proper manner.

As the others have suggested, some time spent with some travel guides would be immensely helpful.

Which places can I travel day trips from bavaria?? Like I want to
travel Paris Zurich Frankfort etc..

Bavaria is a region and a very large one. As mentioned, you'll need to decide first WHERE you want to stay in Bavaria. What time of year are you looking to do this trip?

Which places can I travel day trips from bavaria??

So it sounds like you want one base for all 9 days and to do day trips from there? Paris and Zurich are MUCH too far for day trips from Bavarian cities you may be most likely to base in. Even some cities in Germany are too far away, such as Frankfurt to Munich. Both Paris and Zurich are expensive cities besides so are not great choices on a tight budget.

I want to travel maximum places

Not usually the best plan. Try and do too much and all you see is the inside of trains and buses or the center line of the road, depending how you choose to get around. Also, the more moves you make, the more you'll spend on transport. Breakneck itineraries can also be really tough on kids.

We are 5people with 2kids.

Are you 5 adults and 2 children or 3 adults and 2 children? What are the children's ages?

lso I want to know can we travel in night and roam around in day as we
want to save on hotel bookings.

This also isn't a great idea, especially with kids. And I'm confused: you said you were interested in day trips from Bavaria? You wouldn't use overnight trains for those. Are you meaning places to travel to from somewhere in Bavaria but not returning to your starting point at night?

Last question: why did you choose Bavaria? What is it you'd like to see there?

It is very important for us to know where you are having hotel bookings in Bavaria so we can advise you about day trips. As others said Bavaria is big and neighbors Czech Republic, Austria, Switzerland and other German Lands. Out of these countries Czech Republic is the cheapest, then Austria, Germany and the most expensive is Switzerland. Are you all together 5 or 5 adults and two kids? If you want to see a lot of places and countryside then rental car would be the best for you. Between big cities - train is better.

We are 5adults and 2kids..
And gonna stay in schliersee.

And gonna stay in schliersee.

For the entire 9 days? Are you flying in and out of Munich?

Travelling in mid july. Yes for 9days as it is a free stay

Travelling in mid july. Yes for 9days as it is a free stay

Schliersee is a small town in southern Bavaria on the edge of the Alps, beside the lake after which it is named.
It is the terminus of a rail line from Munich, hourly trains to München Hbf take 56 minutes (I looked it up on https://www.bahn.com/en/view/index.shtml )

How are you travelling there? will you have a car (possiibly two cars for the size of your group), or are you relying on trains and buses?

If you are relying on trains, all your day trips will involve starting by heading north.
Possible day trips are limited to south-east Bavaria (Munich, Augsburg) and the Austrian border city of Salzburg. If you have a car, you will be able to head east or west as well, but not directly south, the Alps are in the way. You could then visit Füssen, with its famous castles (Neuschwanstein and Hohehschwangau). Plus visit other small towns in the Alpine foothills.
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Why did you choose Schliersee? Is this the only place you are staying at?

Schliersee is located in very pretty countryside. Paris, Zurich, Frankfurt (it's with "U", Frankfort is in Kentucky) are well out of your radius of day trips. As Chris F. says southeastern Bavaria with its castles, resort Garmisch-Partenkirchen, nearby Zugspitze - the highest mountain of Germany- you can get there by cable car, Berchtesgaden with its Eagle nest (Hitler's summerhouse), Salzburg would be doable, too. And then, of course Munich. If I were you I would rent a minivan which can take seven people and then travel just around. There is much more to see there than you could in only 9 days. I would not drive for many hours. It's tiring for everyone not just a driver and you would see very little because most of your time would be spend inside the car.

I assume you are staying with family or friends for free in Bavaria.

Would they be able to lend you a vehicle big enough to transport your group? Please check out the insurance issues!

Your other options are train or rental car. Without looking a the schedules, i am going to guess that trains will require transfers via Munich to leave and return to you little town. That will be a real time killer. Plus 7x train fares starts to add up. That would then leave renting a van.

You have to be realistic. Paris is 9-11 hours by car or train. If you want to visit, you really should plan on a couple nights stay.

If you drive and still insist on returning to sleep for free in Bavaria each night, i would probably draw a travel radius of about 4-5 hrs driving time max. Get up the crack of dawn, drive to destination by about lunch, tour for 4-6 hours and then drive home. There are nearby major cities like Munich and Salzburg. Venice, Vienna or Zurich would just be within that driving radius. However, it would be more enjoyable to spring for a 1-2 nights stay. Or just keep it close to home and just tour the little towns in Bavaria.