Oh! I hope I can help, seeing to the fact that my doodle can now stay home for almost an entire day on her own. ^^
We just adopted our new black Labradoodle named Dori a few weeks ago. What happened was that we tried to start leaving her home for 4 hours only a week after she was adopted... NOT SMART. Dori tore through the screen door with sharp nails, and we found her on my bed... -.-
Anyway, I reccomend you start with small time; I went up 30 min. each day. EX: One day I'd be gone for a half hour, the next, a whole hour, the next an hour and a half, and so on. I work with and ride horses almost every day of the week, and n one is usually home at that time, so we put Dori in a little playpin in my father's excercise room, limiting her area to run around in... Which is also a good idea, but be sure to make sure that he has plenty of water and food every day. Also, I suggest you give him a treat that he loves, so that way he associates your leaving with something good. For example, my Dori LOVES Pig-Ears. So now we give her 2, and we love to burry them the night before, 'cause she loves hide-and-seek. If your dog likes to dig, I think maybe you should do that, too... Well, make sure you don't mind your yard being compeltely messed up, though... XD. Anyway, Also make sure that he's in a safe place, where nothing can get at him. It's also good to leave his crate/bed/pillow out there with him, so he doesn't have trouble going to sleep. Well, tell me if there's anything else I can maybe do!