My 8 month old male cat looked to have a scrape on his back. The hair is gone and it's a bit raw. Now I'm not sure if he really scraped it or he has a skin disorder? The scrape is about the size of a quarter. Any ideas?

Did you just find this wound, or has it been there for any period? Is it bleeding? Was he in any situation in which he could have been injured? Is he an indoor cat or an outdoor cat? Is it possible it's a burn? Is he in contact with other animals? You should usually be able to see a difference between an injury-inspired wound and a rash or an infection.

If it's serious, he should be taken to the vet no matter what the cause.

If it is not severe, it might be better if you could post a picture of it. You might get a more accurate guess as to what it might be from. In any case, if you have any doubts, call your vet.