All of the toy-class 9.6V batteries I have seen are rechargeable AA in a 4x4(or "double-flat") configuration. If you buy from somewhere you can know what you are getting then fitment should not be much of an issue. As someone else said, learning to install your connector of choice is a normal part of RC and usually one of the first things you should learn. But, some battery stores or hobby shops carry several types and will install them for you for a small fee.

I would suggest you take a look at www.cheapbatterypacks.com
Under the custom packs menu you can build a pack in the shape you want with the cells of your choice, and then pick your connector from a list with pictures so you can match it with your current battery.
Another place for cheaper packs is www.batteryspace.com
not as detailed, but still a good selection