Woah, slow down here. Optimizing for grades is NOT a bad or stupid strategy, especially when you're young. By doing well academically, you put yourself in a position to do well in the future. Sure, pursue your interests and shoot for real accomplishments--so that when you're applying to college with those real accomplishments you don't need to explain why you didn't get good grades. It's just putting yourself in the best possible position to be rewarded for your work.
Don't short change yourself. Do your best in school, but be pragmatic and work hard outside of it too.