In order for your hunter character to be able to tame and use Blood Beats (which includes the awesome crawgs and blood ticks), you will need to use the item called Blood-Soaked Tome of Dark Whispers. This is a 100 % drop from Zul in Uldir on Normal, Heroic or Mythic difficulty. In other words, kill Zul on any other difficulty than LFR.
The tome will only drop and be usable for hunters. However if you obtain and use the tome on one hunter, all hunter characters on your WoW account can tame and use the blood beasts.