Creatine is defnitely something you can capitalize on, along with that good diet and hard and heavy training. You could also use protein powder, bcaas, glutamine, etc.
At your age, you are in the prime years of your life, and you will grow like crazy just by doing the right things. Capitalize on that. It's only a short time frame in years that you can do that like no other time in your life.
At 16 I started taking protein supplements and creatine. The gains were insane. It's amazing how much your body is primed to grow at that age if you give it the right fuel and training.
One other thing, an Anavar only cycle will do NOTHING except cause major problems. You will make more gains with a high protein diet. You don't want to get stuck with low testosterone problems for the rest of your life so young.
I'm very glad you are here asking this question. The trick to using AAS properly is to build a solid, healthy foundation before even thinking about touching anything. And lots of research!