Hi, i got cat the same age and have some experience here. My little guy is 13ish and on Hills TD biscuits. He was on James Wellbeloved which contained added omega 3 and fish oils. when we switched him to them he seemed to get a new lease of life. Only problem was his teeth were bad and the TD's were recommended by my vet as a hard biscuit. I am not sure if the TD biscuits help with joints but the Hills science range do have other types. I notice no difference from when he changed.
I hope this helps as it would be less fuss than forcing a feline friend to take a tablet everyday.
Chrono :-D