My one year old black lab mix, Harley, keeps pooping in the house and tearing things up when we are away. We just moved in to a 5-bedroom house with a big fenced in backyard. Recently, he has been on a "naughty" streak. My fiancée leaves for school at 6:45 every morning an I usually head to work around 7 or later depending on my shift. Harley has been pooping in the living room and yesterday he chewed up our roommates sandal and my book. He hasn't done this since he was a puppy and we haven't been kenneling him because he has been so good when not being kenneled. I'm not sure if he is having anxieties or what is going on. I'm not sure what to do and would appreciate any help or advice!

Yeah it sounds like separation anxiety and/or he figures he is just punishing you for leaving him.
Can you put him in a crate when you are gone? I know my pit bull realized she needed to behave or else end up back in the crate.