won't say you wrong (cause you don't ;-) but actually there is no need for
DX9 for this.
There where nice mirrors in SWAT 3, which is an old game, and I'm not sure
if it's DX7 or earlier.

Your confusing the question. There are ways around Direct X features that is
true, but what you end up with never be the same as having the actual Direct X
feature to begin with. It could be quality of the image and or speed of drawing
the Image.