X9

X9 may refer to:

• X9 (New York City bus)
• X9, a Metrobus route
• X-9 Shrike, a missile
• ASC X9, the ANSI Accredited Standards Committee X9 (ASC X9)
• Khors Aircompany, former IATA code
• Former IATA code for WOW air
• Secret Agent X-9, a comic strip (1934–1996) created by Dashiell Hammett
• A binary star system located in 47 Tucanae

• 9X (disambiguation)