Yes, if you plan to have them all on at once you need to plan power enough for that.
The other consideration is how long you need to run this for? With 9V (square) batteries, you don't get much current. At the very least you will need to investigate alternative battery technology. You may be better off using the rechargeable battery packs of the type used in RC cars - they can provide 1.2A for about 10 minutes when running a car.