I have one boy whose ears stood up all on their own, probably before 6 months old. The other boy, his ears stand up but flop at the tops.. hes super cute like that, but I bet if I had the groomer tip his ears (shave the tips so the hair was not heavy) they would have stood completely up.
So I'd say either have his ears tipped and see if that helps, or just wait, they will stand on their own or not before he's a year.