Normally if you had IE8 originally, then uninstalling the IE9 update should have removed IE9 and restored IE8 automatically. Did you have any errors or issues when uninstalling IE9?
If you have a restore point dated before you installed IE9 available, then you could do a system restore
using that restore point to undo and get IE8 back.
If not, then you might run a sfc /scannow
command, and check back in Windows Features to see if Internet Explorer 8
may be listed afterwards.