Hi, I'm the developer of the KLN-90B.
The real unit does not calculate a VNAV path and therefore does not output any sort of VNAV information to other avionics or to the autopilot. You would need to fly those approaches with CDFA manually.
The manual of the KLN mentions that the database only contains approaches that the KLN is capable of flying. However, a pilot who still uses the KLN in the real world, showed me, that the database actually contains pretty much all RNAV approaches, even those that the KLN would not be legally allowed. Therefore, there is now hardly any filtering for the approaches anymore. Handy for us sim pilots...
If you are interested in discussing the KLN capabilities further, there is a link to the Discord server on the Github page of the KLN-90B. I only check the JF forums occasionally.