I think Sci Fi is a good choice! Is there a certain park you would like to be in for this meal, or just anywhere?
At MGM, I think Sci Fi would be your best bet for sit down, or Pizza Planet for counter service.
At Mk there is really only Pecos Bills that is sorta "boyish"....they might be too cool for Pooh at that age!
At Epcot, they might like Teppanyaki...with all those flying knives and all, they might think that was neat.
At AK, there really is limited options for dinning, but there is the Rain Forest Cafe that is an adventure if they haven't done that before.
At DTD, you could try Planet Hollywood, or the House of Blues.
At the Board Walk there is the ESPN Club (we really like it there), if they are into sports.