The first three are for Developers, and the last one is for us lot to play our games with the latest version of DirectX 9.0c.
Download the complete DirectX SDK, which contains the DirectX Runtime and all DirectX software required to create DirectX compliant applications in C/C++ and C#.
DirectX Software Development Kit (SDK): Symbol Files
This download contains all the symbol files for this DirectX SDK release for Windows XP and Windows Server 2003.
DirectX Redist Runtimes
This download provides the DirectX end-user redistributable that developers can include with their product.
DirectX End-User Runtime Web Installer
The Microsoft DirectX® End-User Runtime provides updates to 9.0c and previous versions of DirectX — the core Windows® technology that drives high-speed multimedia and games on the PC.
News source: Microsoft
Download: DirectX SDK [432 MB]
Download: DirectX SDK: Symbol Files [34.4 MB]
Download: DirectX Redist Runtimes [44.2 MB]
Download: DirectX End-User Runtime Web Installer [45 KB - 31.7 MB]