Some D3D9 games (mostly Bethesda games: Oblivion, Fallout 3, New Vegas) crashes with an access violation under a D3D9 adapter enumeration ...
... Finally, today's Windows 10 update fixed D3D9 device enumeration issues! (which causes some games to crash to desktop). So yes, it was a d3d9.dll bug (just checked, it has been updated right now) ...
... The issue came with Redstone and WDDM 2.1 drivers, Redstone + WDDM 2.0 drivers combo was not affected. With the last Redstone Update, your D3D9.DLLs (both system32 and syswow64) should be versioned as 10.0.14393.447.