Our Akita was a submissive and excited urinator and by the time she was about 10 months old it completely stopped. We tried anxiety medication from our vet, but that didn't help. It just took time.
Read the article posted above, there's great advise in there about how to aproach him and the do's and don'ts of dealing with it until he outgrows it.
Oh, also, just to be on the safe side, we had our vet do a urinalysis to rule out a UTI, so you may want to consider that too just in case.
I'd think about an ex-pen or putting him in a certain room while you're at work too with a scented piddle pad instead of a crate. That way he's not "ready to burst" when you get home
