When I had free time in my last year of high school, I coded. This was in addition to the excess practice coding I did during classes. When graduation arrived, I was awarded as the best programmer in the batch. Now I am studying Computer Science in the country's best university. This shows that even cutting back on a little laziness could change your future.
Use your free time in school to further skills that you will need later on in university and life, not for games. You have all the time outside the school for that.
One of the Owners once stated that while they respect players who show activity, dedication, and good roleplay, they respect even more those players who know how to put their studies first.