While some dogs will become adult super chewers, at 9 months your puppy's chewing phase is likely almost over, especially as he gets his permanent teeth. While stopping your puppy from chewing may be impossible, you can take measures to curb his pesky habit and prevent him from destroying your favorite objects.
Tire your puppy out. One reason that puppies chew is out of boredom. Make sure your puppy is getting enough play and exercise time daily. This will provide an outlet for his energy and strengthen your bond with him.
Spray objects in your home with a substance that discourages chewing. These sprays are harmless to your pup and have a taste that most dogs find very unpleasant. In fact, after a few nibbles your puppy may not go near the sprayed objects again. Many of these sprays are also harmless to your furniture, including wood and fabrics.
Give your puppy chew toys that are safe, durable, non-toxic and designed for puppies who chew everything. Rotate the toys so your pup doesn’t get bored with them and turn his chewing to you or your objects. Keep an eye on these toys and throw them away once small pieces start to chip off or the toy becomes worn down. Make sure the toys are size-appropriate and consider bones that are safe if digested.
Put away your shoes, clothes, food and other items that your puppy finds enticing to chew. If the object is not accessible to him, he can’t chew it. Although this simple method is not necessarily a long-term solution, it might save a few of your precious items from total destruction. In the same vein, consider crating your pup when you are not home so he doesn’t have access to items you don’t want him chewing.
Tell your puppy “no” and startle him if you catch him in the act of chewing something he shouldn't be chewing. Replace the forbidden item with a chew toy and praise him when he chews the appropriate item. Keep him within your sight, if possible, to minimize the chances of him chewing on anything he wants.