@flynn-farrow I appreciate that people want to kindly offer workarounds, or explain why we who are requesting this might be sadly misguided. It seems it's usually from people who only open a few tabs at a time. Again, we're just asking for behavior normal to all other browsers.
Consider someone who has many (dozens, or even hundreds) of tabs open. It IS possible, and no, the machine WON'T always crash (some of have lots of ram, and may have an organizational style that prefers keeping tabs open to closing them or bookmarking them).
And in that case consider a person who may be on tab x, and do ctrl-t to create a new one, and then maybe use ctrl-1 to go back to a first tab, and then want to go back to that last newly created tab.
Sure, if one has the default behavior to allow ctrl-tab to cycle to the previously used tab, that helps. But what if they visit 2 tabs and THEN want to go back to the last one. Or they may have changed the tab behavior (for other reasons) to NOT have ctrl-tab cycle back to the previously opened tabs. That probably is where this is more of an issue.
I do, and hit this daily since trying opera again, so I notice this lack of ctrl+9, as do many others asking about it in these forums, in this post and others.
And sure, one can use ctrl+1, then shift-ctrl-tab to "backup one". But why must we?
Again, we're just asking that ctrl-9 work like in most browsers, to simply go to the last tab. Is sacrificing that key so bad? again what if it remains to default as it is, but can be changed for those preferring this?
I suspect the divide may be as much about those who leave the default for ctrl-tab to cycle to recently opened tabs, rather than in their order on screen. Different strokes for different folks. But since that provision was made, this option for ctrl-9 to go to the last perhaps just better suits those who turn OFF "cycle tabs in most recent order".