I would like to add Direct3D as an optional graphics backend of a 2D game to get around DirectDraw's limitations (such as the horrid DirectDraw emulation in Windows 8).
Can I do this in such a way that the majority of users would not need to install anything? I noticed that Windows XP comes with some Direct3D files, can I target that version of the runtime?
According to John McCaskey, a software engineer on Steam:
Games which don't use the D3DX helpers (such as Source engine games) don't require running the annoying installer on first launch as they only depend on major d3d9/10/11 versions being installed. However, games that do use D3DX must run it as it's the only way Microsoft has allowed for distributing and checking the version info on the files.
Thus, using Direct3D 9 (d3d9.h) directly should be fine, assuming the user has some version of DirectX 9 installed.
Source: Why Steam Makes You Reinstall DirectX - Rock, Paper, Shotgun