That Kid occasionally appears as Buggy or Crocodile, I'm not saying no. But he doesn't have anything to do with Saint Shanks or Teach. The moment of the meeting between Luffy and Saint Shanks is very important and I doubt that Kid appears out of nowhere to spoil the moment. If Kid showed up to try to kill Saint Shanks, Luffy and Saint Shanks would give him the beating of his life.