I doubt any 2 heads, from the same line, will play the same. Even if they are identical in specs. Shafts, to a point, are the same way. And with you changing the loft down, it makes that head play differently within itself, specwise, & vs. the 9.5. They are 2 different things.
I've got 2 SMT Indio heads, 7.5.(labels showed same specs) One has a DTG FGS Plus shaft in it, and I have lots of confidence in it when I use it. The other, I set up the exact same way and it's a different driver. I've tried other shafts, and it still won't perform as well as the 1st.
Have him buy the 9.5 and set it up 1.