HELP! Separation anxiety leading to chewing?

I have a 5-6 month old Aussie mix named Shiner. He is well cared for, fed three times a day on a schedule, and given water frequently. It's been hot (110+ degrees) so we have not been going on walks, so this COULD be a sign that he isn't getting enough exercise but I do make a point to keep him exercised. He is being fed Diamond Naturals pet food.

I work an average of 20 hours a week and sometimes have 8 hour shifts, leaving Shiner for 9 hours. (30 minutes for travel, each way.) I do not work everyday - I typically have 2 days off a week, and my shifts are usually 5 hours long. I used to leave him in his crate but felt bad about that so, instead, I keep him in my room when I go to work. My roommate works also, but not typically the same shifts so she lets him out to go to the restroom and then keeps him out of the room to play with her dog.

Unfortunately, she was not able to do that today. I returned home and found that Shiner had chewed up a patch of carpet in my room. Most of the carpet was nearby - I don't think he swallowed much but I am still taking him to the vet tomorrow morning to be sure it doesn't cause any blockage.

He also, previously, gnawed on the drawer of my dresser.

What can I do to help him when I go away? I leave him a variety of toys (squeaky plushes and ropes, mostly) and keep the TV on. What else can I do to keep him from destroying my room? He's a very good dog other than this.