My husband and I both work full-time. Stomper is left home alone from around 7:30 AM until around 5:00 PM. He is left in the kitchen (blocked by a baby gate) with toys, food, pottie pads, music and a bed. He does make some pottie mistakes, but is getting better. I always play with him for at least 20 minutes in the morning and all night once I get home. I take him on a walk when I get home from work too. It is tough... I feel so bad leaving him during the day. The most rewarding part is when I get home. He is so happy to see me and cries with joy!
My puppy trainer told me that puppies tend to sleep 16 hours per day, so he should be fine during the day. He still cries when we leave in the morning, which makes me feel terrible. Hopefully in due time, this will stop and he will get used to it.
Once he gets older, we plan to put a doggie door in the kitchen so that he will also have access to play outside. That might help. I don't think dogs like to be confined to a specific area. This will also encourage him to go pottie outside.