R9

R9 or R-9 may be:
* R-9 Desna, a Soviet ICBM
* R9 (New York City Subway car)
* R9 (register), a x64 register number 9
* , a risk phrase in chemistry
* Firestone R-9, a 1940s American helicopter
* Renault R9, a small French family car
* Rohrbaugh R9, a compact pistol
* USS R-9 (SS-86), a 1919 R-class coastal and harbor defense submarine of the United States Navy
* Camai Air, IATA airline designator
* Ronaldo, a Brazilian AC Milan football star
* a fictitious starfighter from the game R-Type