Nine at the top means:
When a man seeks to climb so high that he loses touch with the rest of mankind, he becomes isolated, and this necessarily leads to failure. This line warns against titanic aspirations that exceed one's power. A precipitous fall would follow.
When all the lines are nines, it means:
When all the lines are nines, it means that the whole hexagram is in motion and changes into the hexagram K'un, the Receptive, whose character is devotion. The strength of the Creative and the mildness of the Receptive unite. Strength is indicated by the flight of dragons, mildness by the fact that their heads are hidden. This means that mildness in action joined to strength of decision brings good fortune.