actually, you asked two questions:
first, "without the President's actions, would ACA have passed through Congress's needle's eye?"
no. in fact i already addressed this by saying that obama was the "sine qua non". meaning it would not have passed were it not for him. that makes him the prime enabler of passage, but it doesn't make him the entity that passed it.
second: "What single person on earth did more to "pass" ACA than President Obama?"
a strong argument could be made that pelosi did more, reid might get a few votes, and i'm sure there are many names behind the scenes -- perhaps someday we'll read a story about some unknown staffer who turns out to have been the real hero of the deal. and you will recall that obama came under quite a lot of criticism for not being sufficiently involved, having made his proposal and then leaving congress to hash out much of the details. that said, for argument's sake i see no harm in granting you that no single person on earth did more than he did in terms of getting CONGRESS to pass it.
we really don't agree as to substance. we both credit obama with playing a major role, even the primary role, in making the thing become a law. there are many verbs we can use to describe his actions in the process and many other words we can use to describe his significance to it.
all i'm saying is that "passing a law" is has a specific, constitutionally defined meaning and it is quite specifically CONGRESS that does or does not do this. he can and did do many things, but "passing" the aca was not one of them. no single person can EVER be rightly said to have "passed" a law.
this, of course, takes nothing away from his accomplishment. had he said "the law i GOT passed" or "the law i dedicated my first term in office to pass" or "the law i proposed and pushed and convinced congress to pass" or any of a host of similar things, he would have been exactly right.
again, it's like me saying i give birth to my son. i can take credit for many aspects of his being, but that specific action is something that mrs. unblock did, not me. no single did more to help her through her pregnancy and the entire birth process than i did, but the actual giving birth is something that no man can even take credit for.