Perhaps the number 2 against Ronnie's name denoted Ronnie O'Sullivan the second.
//In some families calling the first born male as the father is a sign of respect .//
I think it's a sign of lack of imagination. I once worked with a bloke called Stan but he did not react to his name unless you addressed him as "Stanley Boy". There were, apparently, eight Stanleys in his family. There was Stan, Stanley, Big Stan, Little Stan, Young Stan, Old Stan, Blond Stan and Stanley Boy. He named his first son Ethelred.