Oh yes, i have seen kids like this. Rare but not uncommon. All other students could sit down quietly doing their work but there will be this one student who cannot sit still, disturbing other students and disrupting the class. Running around too.

ask the school teacher how is his performance during class? Does he complete his tasks?

Check his homework yourself. Does he complete all his homework.

Check the lists of ADHD symptoms yourself against your child.

Ask yourself also were you like this as well when young?

Did you discipline your child when he misbehave? Some parents don't bother to discipline their child, so they misbehave. Then it's nothing to do with ADHD.