I see that alot of rc's take 7.2 volt batteries (c sized batteries) and I also see 9.6 volt batteries (aa sized) I am wondering if you can use the 9.6 where you would normally put a 7.2?

That would depend on the input ratings of the ESC. A 9.6V pack is a differnt size compared to 7.2V pack. Aslo you must take into consideration the batteries mah rating. If the 9.9V pack is like 2500mah and the 7.2 is 4200mah you're wasting your time with the 9.6V AA pack.