How often is he going to the bathroom in the house? mightneed a vet check if it's really often.
Honestly you just need to supervise more and yes if you can't watch, tire him out and then crate him for a little bit.
I think only one time in the whole time I had my puppy she finished peeing before I was scooping her up. Hyper-awareness, catching it EVERY TIME makes potty training a million times easier because it's consistent