We are looking at getting the Paris pass. After doing some research my children that are 4 and 9 will not need a tickets. Paris pass sells a tickets for their ages. My question is are they able to get in the short line with us without a ticket. Is it worth getting the Paris pass or just buy direct from the museum websites?
The Paris Pass is a tourist hose job. The Paris Museum Pass may be of value to you if you plan to go to a lot of included museums and monuments. The kids just walk in with you and at their ages they aren't even going to be asked for ID. The kids are also able to get half price metro/bus tickets. 10 tickets for those 10 and up are 14.90; 10 tickets for kids 4-9 are 7.45.
This is the Museum Pass recommended often on this forum. It will save time entering the most popular museums because you won't have to wait in line to buy tickets. (You will still have a separate security line though, like everyone else.) It can save money depending on what you want to see in how many days. You'll have to figure that out, I think the website tells you what the sights charge individually.
The pass also makes it easy to pop into a museum to see just a few things, or even just for a bathroom stop. Something to consider with kids involved.