The new 10C is about a close to your 9C as a new system can be. You'll be able to use a CamPac to transfer model setups from the 9C to the 10C (as long as you don't reformat the CamPac).

You'd be able to put your 9C transmitter frequency module into the 10C and use all your existing setups. The programming will be virtually identical, with a few added functions. The 7C will have fewer functions and may not suit your needs. The 7C FASST transmitter does have some functions the 72MHz 7C does not, since it's a newer system.