So 9.L was the codename, and its now called 9Ex, like you mentioned. Contrary to rumors surrounding the issue, Direct3D 10 will not be released on the Xbox 360 via a firmware update due to incompatibilities with its graphics hardware. * Direct3D 10 Currently, the only graphics hardware compatible with Direct3D 10 is the NVIDIA GeForce 8 Series and the newly released ATI Radeon HD 2000 Series, which has thus far limited the advent of Direct3D 10-capable applications. It was quickly pointed out that this was not the case, mainly due to lack of support for WDDM in Windows XP.

When 9Ex was still codenamed 9.0L, there were rumors that this would be Direct3D 10 for Windows XP. The Windows Aero user interface relies on D3D 9Ex. * Direct3D 9Ex (previously known as 9.0L): allows full access to the new capabilities of WDDM (if WDDM drivers are installed, of course) while maintaining compatibility for existing Direct3D applications by putting it in a separate API. This is the only API available if there are only XP graphic drivers (XPDM) installed, after an upgrade to Vista for example.

All the details and advantages of Vista's Windows Display Driver Model are hidden from the application if WDDM drivers are installed. * Direct3D 9: this API emulates all Direct3D 9 on Windows XP behavior (and its quirks) in order to achieve full compatibility with older applications. In order to achieve backwards compatibility with previous versions of Direct3D, DirectX 10 actually contains three versions of Direct3D: By using the new Windows Display Driver Model, Shader Model 4 and new, more strict requirements for GPU manufacturers to claim Direct3D 10 compatibility, version 10 of Direct3D represents a radical departure from the practices of previous versions and thus breaks backwards compatibility. A major new feature of DirectX 10 is Direct3D 10 (originally called Windows Graphics Foundation).

Direct x 9