Yes many here have, it is not that difficult. If you know the basics of mendix, you should be fine.
The test is administered online, and its all theory questions: statements, pick the best answer, etc.
A previously asked questions list is not available as we don’t encourage cheating ;)
If you know basic mendix you should be fine, if not than you don’t deserve the certificate
I’d advise going through the academy learnings, they are helpful!
If you do the learning paths and do the tests at the end of each chapter, you will have an idea on how the test looks like.