Obviously the 9000+ MMR barcodes are hackers since no one on the planet can reach this MMR.
Everything about their profile is suspicious, this is what I have been able to collect so far:
100% win record with their race
#1 and #2 spot have been in the top of the archon ladder for a while now.
This is the most interesting finding - these 3 all have a match history consisting only of 1 player custom games, all with match length time 0:00 (this may be because the player is instantly victorious):
What does all of this mean? It seems probably that these hackers found a way to abuse custom games to affect MMR and skyrocketted themselves to the top.
It would be great if other interested readers can look more deeply into what those hackers are doing and post their findings here.