I remember, a long time ago, I looked at this on lichess engine. I remember it gave some Bxb2 followed by Qd4, which is the engine move of engine moves.
I don't remember it now, and im too lazy to find it. But it was something like
Fair enough. an engine can probably hold black's position but I agree with you that it isn't advisable for humans.
As white I'd just play 9.Bd3, followed by Ne2 and laugh at black because his position makes no sense, although I'm not checking this with an engine so that idea may be flawed.
I have to basically conclude that 3...d4 isn't fully playable unless black wants to defend that scary position. In a blitz game I think white wins that almost every time.
Although you may enjoy this line, I would NEVER advise anybody to play 2.Nc3 in the Alekhine. People usually play this in order to avoid theory, but it gets WAY more theory heavy than just having to know the exchange or modern variation.
For example:
My advice is that instead of learning all of this theory; you just pick one variation in the alekhine to learn well. 2.Nc3 gives black all the options and more often than not, he will be much more prepared than you.
I'm not really convinced the 5...c6 line solves all of black's problems. I would not play it against a lower rated player, to be honest. White can just develop and have a good game. That is why I am currently learning a Sicilian.
True, in the caro structures white normally has a slight positional initiative, but then it's a feature of many openings like the French (Rubinstein var.), Scandinavian, and Caro-Kann itself (not to mention the Semi-Slav and with colors reversed, the Colle opening) which are all respected and by no means even close to being questionable openings.
The positions that arise from them are of course a matter of taste, and I was only saying that the Alekhine is not a dubious coffee house defense. Also, white will get a +/= kinda position (with good play) in the 6.Be2 lines against almost all kinds of Sicilians, so that's that.
But in case you're wondering if black can do anything to avoid such positions in the Alekhine's defense, he can try 6...Nd7 (keeping the Bc8) and then g6, Bg7 etc. with a hypermodern set-up which promises a complex positional battle ahead. Check out Topalov - Carlsen, Linares, 2008 (0-1) which shows the dangers of sloppy play by white.