First, calling this a nine book set is a bit disingenuous. It is two maybe three books. Most of the “book” endings seem more like a chapter ending.
I struggled whether to give this a three or four star review.
I really like the story concept, but the writing just left a lot to be desired. Too many unrealistic situations and poorly researched ideas.
All that said I’m starting book eight of nine and enjoying it enough that I’m going to finish them.