Regarding server congestion, I'd like to point out that to my knowledge there were no issues with the midnight releases for Paper Mario, Fire Emblem, and Luigi's Mansion over here. I don't think it will be a problem for Animal Crossing.
Im jealous other people can get the game at 9 in their timezone, even though its the same time, it all comes down to sleeping patterns, im going to be staying up late and have waited 3 hours longer that day for the game to come out. im not mad, just super jealous XD
Also, I can see japan having a clogged launch, but North America has a smaller population and I think less people that play. ACNL is still in the top charts for Japan in sales I doubt it will be like that here