B9, B IX or B-9 may refer to:
Science Prodelphinidin B9, a plant phenolic compound Vitamin B9, another name for folic acid B-Nine WSG, a formulation of the plant growth regulator daminozide Boron-9 (B-9 or 9B), an isotope of boron A subclass of B-class stars
Transport B9 (Croatia), a road part of the Istrian Y highway complex B9 (New York City bus) serving Brooklyn Bundesstraße 9, a federal highway in Germany Iran Airtour (IATA code B9) Air Bangladesh (former IATA code B9)
Vehicles Bavarian B IX, an 1874 German steam locomotive model Bavarian B IX (Ostbahn), an 1869 German steam locomotive model Bensen B-9, a 1958 American small helicopter Boeing B-9 (sometimes referred to as the Y1B-9 or YB-9), a 1931 United States Army Air Corps bomber , a British Royal Navy B-class submarine LNER Class B9, a class of British steam locomotives The former model name for the Subaru Tribeca
Organizations The abbreviation used for the record label Bridge Nine Bucharest Nine (B9), a group of nine NATO members: Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia
Other uses Iceberg B-9, a 1987 iceberg calved away from Antarctica Model B-9 on the TV series Lost in Space, otherwise known simply as “Robot (Lost in Space)“ An international standard paper size (44×62 mm), defined in ISO 216
See also 9B (disambiguation)