Need opinion

It'll take some shaving to get to 9:1. Using the 66 cc chamber volume from above minus 1 cc for the .010" shave already, and a .028" thick head gasket, and the pistons .075" down in the hole (the highest in the bore that you will get with stockish pistons) and assuming 5 cc's in the 4 piston eyebrows, I come up with 8.2 SCR.

You'll have to get to 57 cc's chamber size to get to 9:1 with those thin head gaskets to boot. The core issue with CR here is in the pistons. If you switched to Sealed Power 526AP pistons, that are flat top with no valve reliefs, then you'll get up to around 8.6-8.7 SCR with the thin head gaskets. Another .020" on the heads would get up in the high 8's.

I agree with the above: If you have the heads right now, it would be good to cc a chamber or 2 to see where that it. This is all just roughing in the numbers at this point.

Edit to add: And if you change these pistons, you'll have to pay to have the old ones to be pressed off and these new, inexpensive ones to be pressed on. You'll want new rings too, and probably a cylinder hone. It all adds up.