I have a 4 year old Siberian Husky. When he was a pup he chewed 3 sofas, my Cell Phone , many plants, cords, socks, cigarette packages, got into the garbage... No matter how much we walked him, he would still get into things when we were not home.
Finally we got a crate and started crate training him. I was against crates at first and saw them as a prison, but now I understand that dogs actually like it. He would go into his crate with the door open and fall asleep. Dogs need their own space too. I would definitely get a crate, put some toys in it and reward him when he goes in on his own. He will feel safer in the crate when no one is home, than if you leave him to wander around the house. Good luck!