Z9 was a masculine-programmed R5 astromech droid who served the Galactic Republic and belonged to Admiral Wilhuff Tarkin during the Clone Wars. Z9 was present on the space station Valor along with Tarkin shortly before the Republic strategy conference was set to begin there. When the final Republic cruiser—secretly under Separatist control—arrived for the conference at a dangerous approach speed, Z9 attempted to hail the ship's crew but could not make contact. The Separatist plan to ram Valor with the cruiser was foiled after a Republic squad managed to detonate the incoming ship, saving Valor and much of the Republic fleet around the station.