Yes definitely wait a while after the neuter-you don’t want an infection!! I’d say wait a good month or so for sure-just to be safe.
If you do go for a bath, here’s how I do it…
Get everything ready ahead of time : shampoo (for rabbits is best, but make sure it’s a pet shampoo, your shampoo could damage their skin; Also buy the tearless kind just in case!!) and towels, and a cup.
Get the tub running at a good temperature. It should be very warm but if you put your wrist under the water, it should not redden your skin. Rabbit’s have warmed internal temperatures then we do, so it must be warm but not too warm. If it’d be uncomfortably warm for you it’s too warm.
Don’t plug the tub so it fills up, that makes it scary for them; If you have a bath mat it’s nice to put that in there for them to have traction.
Don’t wear clothes you want to wear later, you’ll be wet!!
Put your bunny in the tub and use the cup to wet him down, lather and rinse. Make sure you rinse really really well. Keep one hand on the bunny at all times so he doesn’t jump and hurt himself.
When your done, wrap him up in a towel to towel dry. Then take a new towel (first one will be soaked most likely) and wrap him and rub him down. Keep an eye on your bunny for the next few hours. They can get very chilled being wet. When I bath I usually wrap them up in a towel and lay in bed with them under another blanky so they stay nice and warm.
Good luck, but definitely wait a few weeks.