2 year old cockapoo acting out

Help!! We have a 2 year old cockapoo that acts out only when we aren't home. He's been doing this since he was a puppy. He's completely house broken but when we leave, he'll poop/pee in the house or chew at the door (only sometimes when he's really anxious.) We try punishing him when we get home, but it's already so far after the fact that it doesn't really do anything but make us feel bad. We kept him in a pen for about 1.5 years (trying a couple times to expand his area slowly but he always did something to make us put him back in the pen), which kept most of his issues at bay, but he figured out how to jump over it recently. Now we're stuck because we can't think of any other way to keep him confined (he doesn't do well in crates). He's so well behaved in every other way but I can't stand coming home to poops and smelling pee everywhere. Please please help!!!!