Nine at the beginning means

Not going out of the door and the courtyard

Is without blame.

Often a man who would like to undertake something finds himself confronted by insurmountable limitations. Then he must know where to stop. If he rightly understands this and does not go beyond the limits set for him, he accumulates an energy that enables him, when the proper time comes, to act with great force. Discretion is of prime importance in preparing the way for momentous things.

Concerning this, Confucius says:

“Where disorder develops, words are the first steps. If the prince is not discreet, he loses his servant. If the servant is not discreet he loses his life. If germinating things are not handled with discretion, the perfecting of them is impeded. Therefore the superior man is careful to maintain silence and does not go forth.”