Nine at the top means

The king uses him to march forth and chastise.

Then it is best to kill the leaders

And take captive the followers. No blame.

It is not the purpose of chastisement to impose punishment blindly but to create discipline. Evil must be cured at its roots. To eradicate evil in political life, it is best to kill the ringleaders and spare the followers. In educating oneself it is best to root out bad habits and tolerate those that are harmless. For asceticism that is too strict, like sentences of undue severity, fails in its purpose.