I just picked my gf's car up yesterday from the body shop after having her front bumper repainted, and the rule of thumb is that you can polish and compound the panel immediately if you wanted to. However, they say wait 30 days to apply any wax/sealant because there are gases that are needing to escape as the paint fully cures. That's usually how it goes, but like everyone else has said, just to be safe contact the shop.