3I

Should Ashoka have seen the nine might join together and cause the problem he was seeking to avoid? Would it have been better to destroy the 9 scrolls?

Ashoka assumed the scrolls were being given to the peasant classes who would know their places and remain loyal to their charge. He was unlikely to foresee that future generations might take it upon themselves to get together.
Seeing the outcome, I do think it might have been better to dispose of the scrolls. Especially when you think that the knowledge contained in them has only been used to enrich 9 individuals (and their descendants), the knowledge has never been shared with the rest of humanity.

He didn't have anyway of knowing at that time how the world would change and the people in with it. >2 Sergeirocks: is right. These people knew their place...did as they were told...and weren't richer than God. I think if he could have foreseen what the potential of the scrolls would produce he would have had a large bonfire and allowed the ancestors of the Unknown Nine return to their trees.

He probably should have given human nature but he assumed that his brother would be selecting people that were unknown to each other and - given the times - would be unlikely to find each other

They certainly didn't post friend request on Facebook or Twitter:)

If he knew how scary things could get then he should have disposed of them.

He probably assumed none of these people would have even made an effort to communicate. But if they were told to keep them secret, the probably knew they were more valuable than they were being told.