Tried it and it worked for the most part.
In IE9, it now works as it should.
In IE8, Google+ appears but StumbleUpon is still missing (but I can live with that).
In IE7, neither appear but no biggie.
I also improved on your fix as I preferred it when it was a hover event than a click event.
To this end, I changed onClick to onMouseOver.
I added a "toggleUnSocial" function to your script and added an onMouseOut trigger to the link.
Then I moved both the onMouseOver and onMouseOut triggers from the link to the div with the wasocial class like so:
<div class="wasocial" onMouseOver="toggleSocial();" onMouseOut="toggleUnSocial();">
The result is here: