Indoor cats have a lot of time on their hands, and that means a lot of opportunity for mischief. No matter how high up you hang your plants, your cat will get to them one way or another.
As a compromise with your cat to keep his paws (and teeth) off your precious plants, you can try getting some plants that can be munched on and enjoyed by your kitty. Some cats are natural grazers, while others will barely even look at your plants.
If your cat has a green tongue, you can create your own indoor kitty garden by buying (or growing your own) beloved cat plants. Here are some good choices for potted cat plants.