9/11 is an interesting example; the youngest Millennials (born '81-'96, according to Pew and others) were only five at the time, so do their experiences really match the teenagers and young adults at the time, who had enough context to understand what they were watching?

In my experience, that's not true at all, to them it was merely an historical event, whereas I quite distinctively remember the shock, despite not even being an American.