Do a search for crate training. A lot of people confuse using a crate for confinement with crate training. You are supposed to be home or only away for short periods of time when crate training. The puppy needs to be let out when it can no longer hold it or it defeats the purpose.
You are locking your puppy in a space that is too small for such long periods of time. Switch to an xpen or a puppy proof room for the puppy's sake.
I'm sure you now know yorkies are known for being difficult to housebreak even under the best of circumstances. With you being gone so much, I hope you keep in mind it is more your fault than his if it takes a very long time (if ever) for him to learn. Best of luck to both of you.
drawlins27 suggestion for daycare is an excellent idea.
