It’s hard to tell from your avatar, is he half black half white or is he sitting in something? I see he has black eye markings and ears. Oh the cuteness!

You should generally see the hormone charged behaviours lessen. Though directly after a neuter they may actually increase. I have read that there can actually be a testosterone surge due to handling of the testes during the procedure. In general though, it takes about a month (sometimes longer) for the hormones to deplete so there is a period that things can be a bit haywire.

As for behavior in the long term, he should become more settled/less “frantic”. Sometimes people are saddened to see an energy level drop or personality change. I believe that is more to do with transistion from baby to adult rabbit and their actual personality coming out, more then a result of the surgery.

Hope it goes smoothly for him. 

most bunnies may not want to eat after surgery, which is normal, but sometimes feeding them veggies will help perk their appetite.

also, keep space limited.. don’t let them jump onto things.

boys to have it easy since neuters aren’t hard compared to spays.

their hormones will calm after a month no more bad/stinky potty habits after

I agree with Jersey, in that a bunny will noticeably calm down within a few months but it is largely due to their growing up, without any hormone surges to get them riled up anymore. He sounds delightful, and I expect the cat will be very pleased since he may be more willing to be friends without fighting.

I wanted to throw out there that he may always be a high energy bunny – not all slow down that much after speutering (or aging). I have a 3.5 year old girl who is hyperactive and full of energy, so your boy may very well stay energetic.

I agree with the others that he may become more hyperactive and hormonal directly after the surgery, but it will settle down after a few weeks.