unfortunately, your site does not allow guest posting, so I cannot try…
that said, looking at the site, your site, probably the wp theme, is doing a lot of specific IE 9 functionality… or rather less than IE 9 stuff… but it will treat IE 9 differently… and IE 9 is much less standard compliant than IE 10…
but even more to the point, your site is loading A LOT of js and css… and IE 9 has a hard limit of 32 css files and 32 js files… you might be exceeding that limit…
could you possible go to forum – options – global settings and try enabling the combined js and css caches and see if that has any impact?