D9

D9, D09, D.IX, D IX, D.9 or D-9 may refer to:

Transport and vehicles

 * Albatros D.IX, a 1918 German prototype single-seat fighter
 * Bavarian D IX, an 1888 German steam locomotive model
 * Bottineau Municipal Airport, FAA LID D09, a public airport in North Dakota, United States
 * Caterpillar D9, a 1954 large bulldozer/track-type tractor
 * IDF Caterpillar D9, an armored bulldozer
 * Denza D9, a minivan by BYD Auto
 * Donavia, IATA code D9, a former subsidiary of Aeroflot
 * D9 road (Croatia), a state road in Croatia
 * HMS D9, a 1912 British E class submarine
 * HMS Imperial (D09), a 1936 British Royal Navy I-class destroyer
 * HMS Trumpeter (D09), a 1942 British Royal Navy escort aircraft carrier
 * Jodel D9, a 1948 French single-seat ultralight monoplane
 * LNER Class D9, a class of British steam locomotives

Other uses

 * ATC code D09, Medicated dressings, a classification for medical products
 * D-9 (video), a video format also known as Digital-S
 * D9-brane, a class of objects in string theory
 * D-IX, a Nazi performance-enhancing drug
 * District 9, a 2009 film
 * The "Divine Nine" (D9), nickname for the National Pan-Hellenic Council, an African American fraternity council
 * Dublin 9, a Dublin, Republic of Ireland postal district
 * Digital 9, a collaborative network of the world's leading digital governments
 * Diensteinheit IX - a military unit of the East German police the Volkspolizei