"Your browser does not appear to support HTML5. Try upgrading your browser to the latest version" on IE9.
IE9 supports HTML5, of course. This happens because this tag is missing from the page's HTML:
<meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=IE8" />
If that tag is not present, and IE by some voodoo decides to render the page in an old documents mode (e.g. it decides to pretend to be IE8), lo and behold, you have no canvas. Don't forget that tag!
Works here in IE9, but I'd advise when styling the page yourself, don't remove any head tags from the exported HTML.