Hi Phil,
Wes Atkinson mentioned your request to me this morning.
At the moment, Adapt does not support xAPI. Although the team at Learning Pool are in the early stages of creating a plugin: https://github.com/LearningPool/adapt-xapi
For the time-being, I'm afraid you're stuck with SCORM. And, as far as I am aware, the only way to play SCORM content on a Wordpress site is to use the SCORM Cloud plugin.
There are LMS plugins for Wordpress (eg. Learndash and Sensei), but they either use their own proprietary tracking system, or xAPI.
You could use Adapt packages with Wordpress, but without tracking - just upload them somewhere publicly-accessible, and embed via an iframe. But that's probably not suitable for you.
Happy to talk about this further if that would help: 07922 146 761
All the best,
Mark