EDIT 23-06-2012 10:24 (CET): Found the answer
EDIT 23-06-2012 10:24 (CET)
Take a look at the bottom answer. That is what fixed the issue for me. IE9 is rendering the right way now.
Working solution for Apache/2.2.15 is to add .htaccess Its prevents caching font files even for https
Header unset Cache-control Header unset Cache-control