I’m with tobyluv, too! Another idea might be to scout your local ads website (craiglist? kijiji? I’ve no clue beyond that) for pet sitters who are willing to come to your house a few hours a day to watch your bun. Screen the ads carefully though, make sure the person is familiar with buns, and check up the references most definitely! (I understand there is a privacy and safety concern with that, but perhaps it is worth it for the bun’s comfort)
A vet’s place may be scary unfamiliar for your bun, and stress him out a lot if there are other animals (to find a rabbit-exclusive vet is difficult, imho). Same for the show rabbits people – I’m sure they’re lovely people, but a change from house rabbit/companion animal to show rabbit/barn may be a bit too drastic for your bun.
Whether you decide on having your friend or a pet sitter come over, please make sure you have time to get them acquainted with the bun! and then you can observe their interactions with the bun and decide for yourself, too.
Keep us posted!