Easy fix? I don't know. What surprises me is when you say it's only IE9. What's on that site is kinda mostly HTML, and then some other stuff that's Idunnowhat.
That right there should NEVER be seen by the browser. I can only assume the other browsers are being all sweet and generous and ignoring tags they don't recognise. IE technically won't even add them to the DOM and really pretends hard that they're not even there, but seeing those template-things leaking into the HTML tells me this might be something you'll want to rewrite. Entirely. By someone who knows both template whatsits AND HTML.
There are also Conditional Comment divs being created, apparently just for IE's 6 and 7... so how's 8 doing? (I'm not on a machine with IE right now, Virtual Box installed fine but Windows is whining, so no Windows for now... sadpanda)
When you say "only IE9"... are you comparing to IE6, 7, 8, 10? or is IE9 the only IE you're testing (are you saying "only IE is a problem, FF Chrome Safari and Opera are totally chill"?)?
I guess you have two options: someone could comb through the code and see if there's just one, obvious cause of this issue in IE, and just leave the rest of the mess until some later time, OR get someone to just rewrite everything and have that person guarantee this new code works in everything from Lynx and IE6 up to the next decade of future browsers (should be possible, but I'm just referring to someone with a lot of front-end knowledge rather than someone with just enough to make a page look okay in Chrome).