No, there’s not a specific certification for HIIT.
In order to teach a HIIT class, your instructor should be qualified to do so, however. That typically means a group exercise certification over a PT certification. A group-ex cert teaches instructors how to design safe and effective programming for cardio/metabolic and strength styles of classes, and the dynamics of working with a group of people.
Personal training is a great and in-depth certification. I have one (ACE). Keep in mind, though, that the scope of practice is different for group-ex than personal training. Since the PT test is more in-depth, people often assume that a good PT will be even better at group-ex than a group-ex instructor, but that’s just not the case; they are different skills. PT’s are trained to look at individual performance and customize from there. It’s a different matter to watch a group of people and keep them all safe; personal trainers will not know about the contraindications / safety precautions that are applied to groups. It’s not covered in their curriculum.
ACE has a workshop for metabolic training. That will go over different styles of cardiovascular training and higher intensity training like HIIT. You might ask your instructors to take this.