DS has been sleeping since noon

He's been sick so I don't really want to wake him but we both have to go back to school tomorrow morning.

I can't miss anymore classes or I'm going to be dropped  

Anyway should I try to wake him up so he will sleep through the night or just leave it be?

Leave it be! My child when sick or on a growth spurt would sleep from like 1 to 530 and still go to bed at 9 no problem, if you want him to be tired by bed time play with him chase him around (if he's feeling better) so he's tired by bedtime