My 8th-grade son is incredibly diligent

If I let him sleep in a bit more
and wake him up a little late in the morning, he gets mad lol
He says he's going to be late for school
Even though there's absolutely no way he'll be late
But his grades aren't coming out well
He is certainly diligent, though
He loves his school uniform so much he wears it wherever he goes
It would be perfect if he were just good at studying lol