I was going to buy leather and had second thoughts. Did you get the cat first or the sofa? If you got the cat first well you should of known better! lol
I made these setter covers for my sofa suite, because throws just keep coming off. Your sofa is going to get a lot more scratches on it!
The covers have to be scratch proof, there are some types of cotton, not all which are scratch proof. Its one of those 100% strong cotton, think about getting some type of cover for it.
Well you seemed to have got the advise for repairing it. I am giving it for prevention.