Steven:
Personally I don´t own a Hi Matic 9, but indeed is a nice and good camera... but I had two Hi-matic 7s, that are very nice , when I compare them to the Konica Auto S2, I don´t doubt that the Hexanon lense is far better. It's more contrast, sharper, has good bokeh, the viewfinder is awsome, the meter when is correctly adjusted works fine, is not as good as the Yashica Electro but It works very well.
I would have them both if I where you, the Auto S2 is a common camera being the Hi-Matic 9 more exclusive, what you do will depend on what you want... to collect or to take pictures.
I imagine some here will point you out other compact Rf cameras, Like the Yashica Electro GSN, the Canonet QL17 III, the Olympus SP...
Anyhow good luck.
Matu