DirectX 9.0c is something you just install, and it should make your game work. If for some weird reason you don't have the runtime, just Google it and download the installer and run it.
If you're still getting an error related to it, then you have bigger problems, eg. you don't have a graphics driver installed, or you don't have a DirectX 9.0c capable GPU. It would probably help to know what game you're trying to run and your system specs.