Doesn't happen. If D3D9Client doesn't run natively on a computer then one can try installing DXVK (i.e. DirectX on Vulkan) drivers but no guarantee for it to work. There is one underlying problem that's difficult/messy to fix and I don't have time for it.
Orbiter uses DllMain() for initialization and DX10+ devices can't be initialized in there which causes some wrappers to fail (like D3D9on12). Initialization is fixed from the OpenOrbiter. Using some later callback to initialize D3D9 device very likely messes up scene loading, alrering callback calling and then crashing...