"Rite NEVER does homework at home. He's in the top classes for 9th grade"

Sorry, it might be a little of subject here, but I just picked up on that. How is it possible not to do any homework at home in ninth grade? Do they have study time during school hours? My sixth grader regularly comes home with homework, sometimes as much as 3-4 hours of it. Granted, he does not use his time during school to do homework, but still....
I sometimes think that my son has too much homework. He can come home with 25 geometry problems, some of them requiring proofs. Besides day to day homework there are long term assignments. So please xplain how is it possible not to do any at home? Maybe we can learn :-)
Ania