Nine Gallifreys was a term for the nine cloneworlds of Gallifrey created using Crypto-forming, that existed during the War against the Enemy. Lady President Romana was War Queen of the Nine Gallifreys. (PROSE: The Shadows of Avalon)
The secrecy of the duplicates was so great that it was rumoured that not even the President knew which was the real homeworld and which was a duplicate. Furthermore, it was said that there were other copies of Gallifrey secreted in pocket dimensions in case the Nine Gallifreys were destroyed.
The ninth Gallifrey was destroyed in a battle of the Mutter's Cluster. The Eighth of these Gallifreys contained Loomstacks that worked day and night weaving Gallifreyan soldiers, throwing biodata soot into the air. It also contained Chronoforges to create weapons for use against the Enemy. (PROSE: The Taking of Planet 5)