Are you sure you mean Chapter Nine? I have just re-read it and Michael does not appear at all, apart from references made to "the others." I wonder if you actually mean Chapter Ten. This is the first stage in the novel where the character of Michael begins to show its leadership, all triggered off by the surprise announcement that Anne is intending to marry. We are told interestingly that out of the group, it was Michael who was the first to respond to Anne and the first to express the thoughts, feelings and fear of the wider group. Note what he says:
"You can't, Anne. For your own sake you mustn't," he told her. "It'd be like tying yourself for life to a cripple. Do think, Anne, do really think what it is going to mean."
It is he who opts to say these rather blunt words to Anne, rather than anybody else, clearly indicating the future role he will play in the group as leader, which becomes more pronounced as time goes by.