DirectX 9 is a collection of APIs for Microsoft Windows that facilitate access to system hardware to facilitate multimedia tasks, including video game programming, released for Windows XP, Vista, and 7.
DirectX is a collection of APIs for Microsoft Windows that facilitate access to system hardware such as the video card, sound card, and peripherals to facilitate multimedia tasks, including video game programming. Version 9 of DirectX was released on December 19, 2002 for Windows XP, Vista, and 7.