Regarding last question.
Alt+tab meant to be used with windows, not tabs. To disable or intercept Alt+tab hacking is required at pretty low level. Alt+Tab works even when other shortcuts do not (Ctrl+Alt+Del, Ctrl+Shift+Esc).
So, as alternative I would suggest using other shortcuts to switch between opened IE9 tabs.
Let's say your IE9 is pinned to the taskbar and it has the first position, right next to Start orb.
Then you can switch between tabs simply doing Win+1.
If IE9 is pinned on the third place use Win+3,
fourth - Win+4