I cant download any of these apps, like Facebook Beta. I HAD it installed at one point, but uninstalled it. Now I cant reinstall it, what gives? Downloaded and installed the DX9 runtime, rebooted, still says I don't have it.
DirectX runtime should not be needed for any Windows Store apps. The whole idea of Store apps is that they include all dependencies so you don't have to install anything else.
DirectX is also mostly just for games, non-game apps don't even have full access to the DirectX APIs. As far as I know, only desktop apps (Steam/Origin/disc games) and Xbox games (play anywhere) can fully use DirectX.
What's the actual error you get, and when exactly are you seeing it?
I get what you are saying, but if you go to the app I referenced in the store, on PC, there is clearly a requirement for DirectX 9. So I'm not sure where your information came from.