Nine at the Top is the final line of Progress, a yang line in a yin position at the very summit of the upper trigram Li (Fire). 'Progressing with horns' means advancing aggressively, using force rather than virtue. 'Subduing one's own city' means turning this force inward — dealing with problems within one's own domain.
This is a complex line with mixed results: 'danger, yet good fortune' — the aggressive approach works, but at a cost. 'No blame, yet perseverance brings humiliation' — you can justify this action, but making it a habit brings disgrace.
As the card depicts — a warrior standing at a city gate with drawn weapons, asserting authority through force. Sometimes necessary, but the marks of battle remain.