Depending on how long you've been out of the house, your puppy could be experiencing separation anxiety. It is best to let him out of his cage whenever someone's home. And crate him when no one is home (not for too long, I would say 2 hours max per time). While crated, it ensure he is not soiling or chewing your walls and furniture. If you let him out and he does these things, he might learn that it is appropriate to do so.
Your puppy is still young and needs to be trained. If you have taught him what "No" means, it'll be easier. Encourage him to roam around the house when someone is around. Whenever he does something inappropriate or close to inappropriate, (ie: sniff your shoe or sniff the power outlet), enforce by saying a firm no.
If you haven't taught him "no", please try to asap. I taught my dog "No" when he does something inappropriate and I say the word "No", then I would isolate him for 10 minutes.
Most puppies and dogs like to be around people, so by isolating him would let him think about what he did wrong, and as well as linking his previous action to punishment.