With an interesting and new premise, Missing 9 seemed like it would break boundaries, and in a way it did but unfortunately it never fully managed to reach its' full potential.
The show starts off strong by wasting no time dumping our cast on a deserted island after a plane crash. And with the island events unfolding via an unreliable narrator suffering from shock, we learn bits and pieces of the truth in a muddled way that kept things interesting and intense. The show also pulled no punches, revealing early on that it was willing to show how the lengths people will go to in order to ensure survival. It also became apparent that things were planned far in advance regarding the plot as previous points come back into action episodes later.
And while this was great, the show never manages to fully become as great as the writing promised. There are flaws, such as the logic behind the investigation team. Their actions make little sense and are the least fleshed out aspect of the show; normally it's a small matter only they play a fairly large role and it shows. The "villains" so to speak, while fairly chilling, are also a bit cookie cutter like in their actions - a combination of acting and writing.
The majority of the cast, however is great. The plane crash survivors manage to play their two lives (of survivors and stars) fairly well and the group as a whole gets along great, even as relationships crack and strain.
The show just seems to be missing that something special to really make it take off.