Hello SevenBeginner, and welcome to Seven Fourms.
Not sure why it was doing that before, but by default when you click on the pinned IE9 icon on the taskbar, it will open one instance of IE9. Clicking on the IE9 icon again will just show you it's taskbar thumbnail preview
with more than on IE9 instance or tab opened. If only one IE9 and/or tab is open, the clicking on the icon will minimize/unminimize the window.
However, you could open another tab in IE9.
You could also right click on the pinned IE9 icon on the taskbar, and click on Internet Explorer
in the jump list to open another instance of IE9.
Hope this helps,