He keeps meowing and literally will not stop walking around. Is it the anesthesia wearing off or is he that pissed he got shaved? And of course he is freaking the other cat out which is hissing at him now.
Maybe its his way of scolding you for doing something he didn't like. You know, cats work hard to train us how to pamper them. I would play with him until he passes out to get all that energy out of his system. hopefully his excitement will subside and things will go back to normal for you.
It sounds like he is reacting to the anaesthetic wearing off. My cats are always super grumpy after they come back from the vet, no matter what they've had done.
Did they shave a large patch of fur off? Mine don't usually notice this until it starts growing back.
Did the vet give you any pain killers in case his teeth are hurting him?
Once he ate he was OK. He couldn't eat since 9 PM the night before because of the anesthesia and the vet didn't want him eating right away when he got home. That was a little scary when he literally would not sit still at first.