Is there a way in IE9 to see styles that are originating from the user agent?
Similar to firebug's show user agent css feature.
Today I thumbled accros a nice site. Internet Explorer User Agent Style Sheets
You can find there all user agent styles of the last IE Versions listed in a nice table. Of course you can open developer tools on any major browser by hitting F12
Within IE11 you'll see a picture as shown below. Navigate to DOM Explorer open Calculated Style at the right hand and disable options marked with red.
Right now I can't find a working IE9 installation on one of my computers. So I hope this may still be of any use for you.