I think you mix up some editors. The latest version of the CKEditor is to my knowledge 2.4.8 and works with all Mx versions from 5.21.0. Where are you getting the version 4.9.2 from?
The library in the widget hasn't been updated for a long time. The CKEditor library in the widget is currently at version v4.3.0-master-d769233. I don't have any plans on upgrading the library, as this widget is using a whole lot of external plugins (upgrading most likely will break a few of these libraries).
You can ask Support for a ticket, but as this is a feature request, I don't think we will be upgrading it anytime soon. Of course you can attempt it yourself, the widget can be found here: https://github.com/mendix/CKEditorForMendix.
From my end I will make an impact assessment and do some tests to see if it is possible to upgrade the library without too much trouble. Due to other projects I can't promise a date yet.