ITA with mon - and unless there's something else missing from the story, I don't understand why the Principal would be involved.
FWIW, re what might lead him to punch like that - it could be anything you've thought through above, but it also might be just pure frustration at having to write (if he's got a fine motor issue, especially if it causes him pain to write). Have you noticed if he rubs his wrist when he's writing or holds his elbow or anything like that? Our dsygraphic ds used to get *extremely* upset about having to write when he was your ds' age (prior to our understanding he's dysgraphic). Our ds is an *extremely* laid back personality, probably one of the most mellow people I've ever known and he was the same way as a young child - until he had to write. He through pencils, stomped, kicked, tantrumed etc when he had to sit down to write - partly because it was really difficult, but also because it hurt, and we didn't realize it. I can totally imagine that if he'd been 5, and an OT told him to write something and he was frustrated by it all he might accidentally lash out and hit - not meaning to, but more of a reflex at the frustration of it all.
Have you talked to the principal or OT about it? I'm curious what they have to say. Whether or not you decide to homeschool I'd seriously look at what benefit (or not) your ds is getting from the OT work - if it's stressing him out, I'd be inclined to drop it for now or look for a different solution - maybe add a tiny bit of fine motor into his private OT?
Best wishes,
polarbear
