I know it's maybe a silly question but it's really interesting to me. I know we can create apps for Windows Phone 7 using Silverlight or XNA, but is it possible to develop pure DirectX 9 applications which can run on Windows Phone 7?
Thank you for your answers and time in advance.
No you cannot use directx-9 to make apps for WP7 (without jailbreak). Making Silverlight or XNA app you are using it indirectly, though.