S9-43 is a character mentioned in Fallout 4.
S9-43 is a runaway synth in 2287. Their last known location is near the Boston Airport. The search and retrieval of this synth has been postponed by the Institute as the area has been deemed 'too hazardous', likely due to the recent Brotherhood of Steel arrival at the airport.
S9-43 is mentioned only in Fallout 4.