I actually did something very similar a while ago for the Alteryx community, if I remember correctly they used "classmarker" for their certification exams and I integrated with that platform to grant roles and through them badges. There was additional complex logic because certifications depended on each other, e.g. someone who doesn't have "Level 1" can't do a "Level 2" certification ("duh" you might think, but yeah, that needs to be implemented 😉) and those certifications would also expire after a pre-defined amount of time which required additional logic. It was a fairly complex project, definitely not something I would be able to explain in a forum post.
But your general idea of how this will go is correct.
You would set up a "webook" that is an endpoint in Khoros terms which would receive a request that someone has completed a certification. What might be a problem is that you need to map Khoros users to Skilljar users if they are not already somehow linked via an SSO id or some common identifier. E.g. you need a way to determine which Khoros user did the certification when you receive the webhook request to give that user a role.
