Well the only thing that truly comes to mind would be caffine.
To start off NOTHING will make you magically stronger, even with roids you still have to spend time in the gym.
For more energy, eat COMPLEX carbs, lots of pasta that kind of stuff.
I’m a big fan of power naps also, lay down (don’t even have to sleep) for around 15 minutes and get RIGHT UP when the time is over. You’ll feel great.
At 15 (I myself am that age also) the only supplement I would reccomend would MAYBE be added protein if you do not get enough in your diet. However even that has draw backs, such as you have to triple your water intake or you’ll cramp up really easily.
At 15 you should not be seeing any plateus if you are lifting, so creatine should not be really necessary.
My suggestions are, better your diet, and increase rest. Those two NATURAL things go a very, very long way.