Our trainer said that most dogs are given up at the age 8-24 months of age, and she also mentioned that at the age of about 10-12 months dogs teeth set in the jaw, which creates a serious need to chew on hard things.
Knowing those two things, and recognizing the breed (I got a Rottie! :) here are my thoughts on the issue...
For that to happen, your pup must be alone long enough to actually damage the wall. Seeing that it's a difficult stage, and your dog is not handling it well enough, I would make sure that
#1. you keep him well exercised every day (for example, I am 100% certain that my Rottie could spend 2 hours in the house right now without chewing on anything, because of the 4 miles we walked not so long ago, and she's too tired to get in trouble.)
#2. I would sign your dog up for daycare, when you are unable to watch him. He cannot be trusted to be alone in the house at this point, so that means you always have to be present when he is home, to "unlearn" the unwanted behavior, and to realize that it's unacceptable.
#3. Every time I'd see him start chewing on something you don't want him to chew on, I'd provide an appropriate substitute (toy? marrow bone? bully stick?), and praise and encourage him to grab on to appropriate "chewies".
#4. I'd make sure that his mind is exercised every day as well. He needs every day training and a job, especially during difficult stages, such as this one. The more tired in a positive way he is, the less trouble he'll get into.
Hopefully you are in classes with him (as all 1 year old pit bulls should be ;) , and your trainer can help you with other tips.
Best of luck!