Ok nearly done with 9S playthrough - the huge ass sea machine is down, and got past the Adam kill by 2B (which obviously you don't experience since you're taken away after the missile blast). In the bunker right now and i think it's just nuking Eve left.
All-in-all, combat with 9S works best (for me) with the "set things on fire" chip for hacking, and then using fist weapons with the charged attack. He's slow anyway. Also found Masamune so some weapons are at max level now.
And f*** the "Idiot savant" sidequest. I mean, they couldn't concieve an harder hacking minigame.