It's not displaying in IE8 either.
I can see that everything but your CSS (don't even want to attempt to wade through the dozen or so different stylesheets) looks about right.
A guess is that the radio buttons are located a few hundred pixels off of the screen or have "display:none;" or "visibility:hidden".
Your syntax, including closing tags are right for your inputs and your XHTML transitional.
Actually with transitional, you could close them anyway you wanted to and they would still work correctly.
Again, you need to look very closely at your divs' CSS possibly coupled with your list's structure and styling. Something about IE doesn't like the styling.
When you find the culprit, you can usually fix the problem with a conditional statement for IE in the head.