When you're an adult you have to take financial risk to pay for time to work for free time to work on what you believe in. When you're a kid, your parents pay the bills and the health industry allows your parents' health insurance to cover to you- you have no financial risk. However, the devil's bargain is that you waste eight hours a day at school. It sucks, so get working on what matters.
You write well and you are clearly smart so you're also smart enough to get the grades you want. Get over yourself and stop looking at it as intellectual stimulation- instead, put in the amount of work necessary to get the grades you require. If you want to go to college, look up the average entrance scores and give yourself enough wiggle room to get in with ease. If you don't want to get in college, just put in the work to pass and push the rest of the time towards learning what it is you want to learn.