Nine at the beginning means:
There are exceptional conditions in which the relation between leader and followers changes. It is implicit in the idea of following and adaptation that if one wants to lead others, one must remain accessible and responsive to the views of those under him. At the same time, however, he must have firm principles, so that he does not vacillate where there is only a question of current opinion. Once we are ready to listen to the opinions of others, we must not associate exclusively with people who share our views or with members of our own party; instead, we must go out and mingle freely with all sorts of people, friends or foes. That is the only way to achieve something.