Push Opera tabs all the way to the top

Right mouse button on the interface -> Appearance -> check "Personal Bar"

Edit : more simple way : menu "View" -> Toolbars -> "Personal Bar"

You can find more details about this toolbar on this page. Note though that if you can easily move things to this toolbar, it is not a "folder" from your bookmarks, like in Firefox. Items added there are added to your bookmarks, but if you remove them from the Personal Bar, they will remain in your bookmarks.

There doesn't appear to be a way, at least it's not listed on their shortcuts page and I didn't find a way to do it. Though you can customize shortcuts, you can't add new actions and there aren't any actions for visiting tabs 1-9. I customized Opera to use Ctrl-PageUp/PageDown to go to the previous/next tab, but it's not as fast as going directly to a tab.