kingcon works fine on os3.9 , you just need to do some changes...
its abit tricky but it works fine here, but its long since i installed it so i probably wont answer to precise on how to do so.
anyway for me , i installed 3.9 cd striaght onto my setup without any major problems, the installer is pretty good.
the only prob was to get the cdrom booting with a floppy.
imho os3.9 should have been delivered with 1 floppy and 1 cd...
but a good tip is , tell us your setup and maybe someone can make a boot disk for you (if they have simmilar setup).
cheers