I believe that many of the IE8 and 9 problems people are posting are due to an error in the way the doctype is presented with the RDF module enabled.

I would replace the doctype designation there with !doctype html, per the abstract http://www.w3.org/TR/rdfa-in-html/, specifically the section 2.1 (Html5 and RDFa conformance).

I think this will fix many of the bugs you are seeing with IE8/9.

Thank you!