To me the habits should start earlier than HS.
In my one daughter's case, she was constantly belittled by her grade 6 teacher. I had a chat with her and things improved. Fortunately we moved and her next teacher turned her around and she graduated college with an honors degree.
My son had the same teacher and he was also the coach for basketball and volleyball. He had an incredible effect on my 2 kids. I remember getting a call from my son's previous teacher. Well actually it was from a psychologist saying my son had no issues. I asked her what she was talking about. She told me they tested him because he wasn't finishing his tests etc. They suspected he might be slow. It turned out he was fine he just a very detailed type of intelligence. They told him he had to work faster and he did.
My daughters all had to work hard but my son just didn't. You always knew when my daughters were writing exams and my son it was life as usual.
Most players I have observed over the years all had different development rates in academics as well as BB. Some just have it easier than others in both. They are what they are and if they don't understand that marks will get them more academic money and open opportunities by HS you have to hope the light will go on eventually. For those who are not academically inclined all is not lost.