No, 1.0.0 is based off an older stable branch; the master branch is what will become the 2.x line. You can read a bit about the version plans here: http://css3pie.com/2012/05/15/pie-1-0-0-released/
You're welcome to try the master code but be warned you'll have to build the code yourself and there's a good possibility of other issues as that code is not yet stabilized. If you want to continue using stable code then there is no fix available for you, you'll need to use a different solution for this case.
I recommend against using IE9's emulation modes to do IE6-8 testing in general, as it is often inaccurate. See viewtopic.php?f=4&t=1206