I've submitted a new version that uses D3DCompile2VKD3D() directly, including from d3dx9.
This does require the latest version of vkd3d, which can make e.g. bisecting difficult. This is not a new problem, but it was raised to me off-list. Unfortunately there is not really a way to prevent this without significant changes. The vkd3d headers do not include any indication of the version, and we cannot rely on compile tests since we cannot access config.h.