The Ninth Cyber Legion was a Cyber Legion.
The Ninth Cyber Legion invaded London in 2012. It was led by a Cyber-Planner and a Cyber-Leader. Their Cyberfactory was full of Cyberman storage units, guarded by Cybermats. It also had an Operations Chamber where the Cyber-Planner and a piece of the Eternity Clock were. This Cyber Legion was destroyed by the Eleventh Doctor and River Song by shutting down their thermionic core. (GAME: The Eternity Clock)
The Ninth and Eleventh Cyber Legions once joined forces to conquer the planet Agrippina in the Tiberian Spiral. The Cybermen were ultimately successful, with the human colonists of Agrippina having only antiquated anti-cyber guns to defend themselves. (PROSE: Ghost in the Machine)