R4-J9 was an R4-series agromech droid, one of three droids assigned to a droid pool that included R4-S2, which managed to survive the Twi'leki scout ship crash and repair itself in 90 BBY. The unit and R4-S2 went on to work for the administrative droid, QS-2D. Both agromech droids surveyed mineral deposits on the moon of Uffel and set up mining operations to obtain raw materials to manufacture droids.