I have no clue why J9s has lower equity than J6s on that board. It's still so close you felt either way, but that is wierd.

As far as the ABCD theorem, you have a good point. I remember when I played 2nl-10nl and it was quite hard, nearly impossible, to put most players on an accurate hand range. It's still hard at 50nl, as they still do alot of crazy shit. But you can still apply the ABCD theorem to your range and how you should play the hand.