Aw, your sweetie is so adorable!
I haven't had to leave Kingston alone yet, but this coming month I'm going to be working full-time and going to school full-time (bleck!) and my bf is also going to be working full-time
We are unsure what we're going to do... we may get him a little girlfriend to play with (this was my secret evil plan all along according to DBF, muhaha

) or else let him spend the day with my dad who offered to be his babysitter lol. He also has a dog that gets lonely so this may work out for the best of both worlds.
I'm not sure what you could really do

You have to work to make a living, it's just hard to explain that to a cute little puppy

I'd make sure he has plenty of room to play (maybe a closed of kitchen with protective baby gates?) and food, water, and TOYS! Then when you get home be sure to give him extra lovin'
Good luck