It does change the font-size to 9pt; I've just tried your code on a test page of mine which had 16px before (but it's white font on a light gray background so it's hard to see). Have you altered browser settings? IE7 has check boxes in tools/internet options/advanced to reset text size to medium for new windows and tabs which is normally unchecked. Firefox in tools/ options/ content has a check box to allow pages to choose their own fonts which SHOULD be checked to allow your 9pt to be used.
However, with pt or px the font-size will not change in IE if a viewer changes the text size, but it will in Firefox.
In fact Firefox is following the rules to allow partially sighted people to alter the text size while IE6 was breaking this rule because there was no way in IE6 to increase the text size except by using a special stylesheet that disabled people can use. IE7 has a zoom facility which increases everything on a page including images so that the whole page formatting stays the same and this is a good feature.
Code downloaded to my PC will be deleted in due course.
WIN7; IE9, Firefox, Opera, Chrome and Safari for Windows; screen resolution usually 1366*768.
Also IE6 on W98 with 800*600 and IE8 on Vista 1440*900.