As far a night weaning a 9 month old, it is hard to say because all babies are different but many BF babies can go without Night feeds by this age. You will likely have to increase daytime intake.
I found as I began to space out BF during the day (how many h between BF now?) My LO started to take more milk per feed. I did find it was a slowish process b/c you want them to take the lead as per BF guidelines. You may want to drop one night feed at a time, give a few days for him to compensate. Night feeds can become a prop for a baby. You are right that it may confuse him, but not to yours or his benefit in the long term. Can your partner tend to some of the night wakes?? I found if my husband went in my LO did not expect food and would settle.
I found that by the time my LO was 9-10 months the flexible routine was less effective. So even if my LO had a short nap, I only made small adjustments to other naps or BT. It did lead to a few rough days/nights (but you have that anyways) and I found baby would adjust.
The avg awake time is 3-4h, some like even more. And it is not necessarily the same per awake period. I found my LO liked far above avg awake time in AM and much shorter in afternoon and before bed. Some babies are the opposite. So I would increase by 15-20 min consistently for a few days... See how it goes then possibly push again.
I hope I addressed everything, sometimes I get on a train of thought and lose where I started