Its a boy for sure. Orpingtons are less likely to be mean roosters than lots of breeds. If you allow your kids to handle him and you don't have other roosters for him to compete with chances are great that he will always be super sweet. I had one orpington rooster I handled a lot when he was young. Even when he was a full grown rooster with tons of other roosters around, He ran to my feet when I came out and always wanted to be held. I'd say give him a chance and if he acts aggressive at some point be ready to get rid of him.
