Well, that's not really time travel. Like a historian or an archaeologist, Rand only knows from the past from his source. And a single individual's eyewitness account, at that .

As to the main point, however, I of course agree that Rand destroying the Aiel will likely have something more to do with the Way of the Leaf, and that the followers could justifiably be considered a remnant of a remnant that he saves, except that this is only half of the prophecy. The rest of the Aiel must be destroyed, and I do not believe leaving them to pursue the lifestyle they've followed for millennia can be counted as "destroying" them. Unless we follow it through all the way to the end of Aviendha's vision, but I cannot accept that for two reasons:

1- It means that Aviendha's vision is actually true and inevitable,

2- The prophecy clearly states that this needs to be Rand's responsibility, and I have a very hard time blaming Rand for decisions made by others after his death in stubborn pursuit of a lifestyle they chose long before his birth. Rand's actions may be responsible for the circumstances that lead his children to make that decision, but Rand is shaping the entire world around him, there's unlikely to be any event in the future that cannot somehow be connected to Rand's actions, if only because Rand is probably responsible for the continued existence of the world that makes that 'future' possible anyway.

Rand's epiphany was about being less controlling of everybody's life and allowing them to make the right choices of their own volition, I cannot find a way to make this consistent with blaming Rand for the destruction of the Aiel dozens of generations after his death just because he created a world that bored the Aiel.

Which, to return to my original point, leaves that prophecy of "destruction of the Aiel" unaccounted for, either in the present or in Aviendha's vision, and therefore conclude that Aviendha's vision cannot happen.