While the N9 and the Lumia 800 use the same amazing Nokia hardware, neither of those runs Android. Nokia made a decision long ago to use MeeGo on their last great in-house smartphone (the N9), while shifting to Windows Phone shortly after on the Lumia 800. Now, N9 can run Android 4.0 what means that Lumia can also run Android 4.0 sooner than latter.
Whatever, if you're disappointed that Nokia has gone down the Windows Phone 7 path, leaving MeeGo developments on somewhat of a standstill, you can given Android 4.0 Ice Cream Sandwich a try. You can follow the steps which shows in below video.