OS3.9 comes with ViNCEd that is way better than KingCON. Unless you spend a lot of time booting into first CLI (booting without startup-sequence) and want more than commodore CON in the kickstart, you are way better off using ViNCEd.
Bonus feature is that Thomas Richter is here to offer support as well.
(Which reminds me of a "bug" I should have reported)