I would wait a week or two until the male hormones start to subside. They should be okay waiting that much longer.
Whether you'll have to feed him differently, or stay up to keep an eye on him, depends on the type of surgery. If they remove the pom, they should send home pain meds and an E-collar; and in that case you'll want to make sure he's in a small cage with the pouch close to or lying on the floor, so he won't climb, fall and get hurt. It should take three or four days for him to start feeling better. If they leave the pom on, he should still get the pain med and E-collar but there's a chance you won't need the collar. Watch him very carefully for at least several hours after you bring him home, and especially for several hours when he first wakes up. If you see him start to worry the site, then get the E-collar on him. In that case, you may have to hand-feed him.
I've had three boys neutered with poms on, and all three were perfectly normal within an hour of the surgery. I didn't have to do anything differently; though being a worried mom I did stay up and watch them to make sure everything was okay.
I'm glad your vet is squeezing him in early. Nothing better than a vet who cares!