IE9 applies both the the filter as the -ms-transform , therefor if I want to rotate 5dg, it rotates twice to 10dg. Also the rotation using filter gives a black background.
I had a similar problem. I just added conditional styling for ie7, ie8 & ie9. For ie9 I just used -ms-transform. For ie7 & ie8, I used both filter and -ms-filter. This fixed the double-rotation and the black background. HTH.
merging this into #73
thx for the report, gusy!