Minions serve the evilest person they can find. Surely Osama Bin Ladin would have been the most evil person in 2001. But as we see in the Minions movie, they began serving Gru in the 60s. That means that nobody was as evil as Gru. Not even Bin Laden.

What the ♥♥♥♥ did Gru do that was worse than 9/11? Or maybe... it was Gru who did 9/11. And since the minions serve him and do the dirty work, they must have been the terrorist.

Yes, the minions do indeed remember 9/11. Because they did it.