I am sorry that this is not something we can diagnose. Even seeing the cat in person would not help, only a vet can tell whether this is a bad lump or not. There are MANY things it could be and not all of them are bad news. But at 9 years old, which is fairly young, please don't take chances. I am sure your friend would be very distressed to find out it was easily cured but she waited too long to have something done to help her kitty. I think the key here is the fact that the lump is painful. Advise her to see a vet. Please.