I can't speak for "really huge men," since I probably don't belong in that category. But I think that any guy who's that big has not only accepted the fact that no woman can take all of him, but considers himself lucky when he finds a woman that isn't completely intimidated by him. Seriously, 14 inches is a length that most women would flat-out reject for fear of injury. If you're that enthusiastic about sex with him, then I'm sure he's very satisfied with "only" fitting nine inches in. I'm 8" long and have bottomed out before, but it never made me less satisfied. If anything, it made me feel good that I was filling her up to the max.
I'm not sure there's much you could do about taking more length. I'm not a doctor or anything, but it's my understanding that the vagina has a lot more flexibility for girth (e.g., a baby's head) than for length. I don't think it stretches much lengthwise. Best case scenario is that he bottoms out and can't go any deeper. Worst-case: he injures your cervix from thrusting repeatedly against it. You could continue trying to carefully take more of him, but I think you're going to reach an absolute limit, if you haven't already.
Like I said, it sounds like he's really happy with how much of him you can take. Given his measurements, that's probably the most you can hope for.
