A male neutering is a quick and straightforward affair that only rarely causes complications. I do understand your nervousness though – there are never any guarantees and it is after all our babies that are going under the knife.
You can use any sort of bedding that won’t stick to a wound, i e pretty much anything that isn’t wood chips or similar.
In rare cases the bun might need warming up with a warm waterbottle or handwarmers in a towel. This is for buns that are very lethargic and out of it when they come home and refuse to eat.
Once the bun eats something, you can relax quite a bit. Fresh fragrant herbs can often spark an appetite. You can give him a treat or two if he wants them – the important thing is to get him eating, what he eats is of less importance.
Many male young buns will be as bright and energetic as ever once the anaestesia wears off. It’s still wise to restrict jumping and climbing etc for 5 days to a week. He doesn’t have to be caged all that time, he can have supervised playtime.
Check the incision area twice daily. This is easiest done if you can get someone else to hold the bun while you check for swelling and seepage. Some swelling and bluish discoloration of the skin is to be expected, but if one or both scrotal sacks swell up to the size of ping pong balls, its (rather obviously) time to call the vet.
Male rabbits can have viable sperm left in their vas deferens up until 6 weeks after a neuter, but I’m assuming your girl is neutered so there will be no risk of of an oops pregnancy anyway.
Allow 2 weeks or more before you start bonding procedures. It is common for rabbits to go through a period of “post-neuter-craze” after their neuter. This means a shorter, self-limiting period of extra hormonal behavior such as poop- and pee-marking, territorial aggression, courting behavior etc. It generally subsides after 2 weeks but can go on up til 8 weeks and still be within the scope of normal.