I've had a cat almost continually from the time I was a young girl and I just have to say that as a rule cats really don't like clothing.
They have fur they can get overheated so watch the temps he's wearing it in. Also..watch carefully for chewing. Cat's can choke on yarn so if he chews it he shouldn't wear it. I don't think I'd let him wear it if I wasn't around...but maybe that's just me.