I hope the little kitty is ok. I only have experience with my own cat fluffy who had to have his front right leg and shoulder amputated due to him having cancer, I have no knowledge of club foot. My cat adapted very well, he was angry with all the stitches he had but the first night we got him home (we payed for an extra night in the kitty hospital even though they wanted us to bring him home the same day as the operation) he was jumping up onto the living room window to have a nose about. He is very active in the garden, he uses the scratching post, he still thinks he has four legs, I can see his stump moving when he is in the litter tray, he still thinks his leg is there. I am sure the vet will advise you well judging on xrays etc.
I hope the kitty doesn't have to have an amputation but if the poor little thing is in pain then maybe it's best. Cats adapt quite well to having 3 legs, we did plenty of research before we went ahead with fluff. It was very upsetting at the time, I don't think fluff would be here with us now if we didn't go ahead with the amputation, but that was cancer so it's a totally different thing with kitty having club foot.
I hope all goes well with kitty regardless.