https://ptr.wowhead.com/news=289371/...location-found
As of right now, the way for hunters to be able to tame Crawgs and Blood Ticks is by hearthing away mid-fight in a heroic Zul encounter. He must be engaged, but die after you've hearthed.
EDIT: It was confirmed by Muffinus/Jeremy Feasel that this is not intended.
https://twitter.com/Muffinus/status/1076675766211862528