My advice besides the crate training is to empty him before you leave. Make time to go on a short walk until he goes potty before you leave.
My dogs sometimes will poop three times on a short walk. They actually strain to get everything out of them to mark as much as the neighborhood as they can.
Our female even backs up and pees on trees.
If the he is empty & maybe give him a chewy to keep him busy, and a really nice blanket to sleep on. They love snuggling certain things.
He's going to have a hard time pooping/peeing in the house if he has nothing inside of him.
