I've been torn between nine and four as well in the past, but the deciding factor for me is how close I am to a five- I test pretty much even on 4 and 5, with 9 coming in 3rd. Not only that, I don't relate to the 8 or the 1 AT ALL.
I can be the peacemaker for stretches at a time, but I always assert my individuality in the process, and I am so greedy with my time like a 5. My needs typically come before those of others. I try to be selfless but my first thought is always how something will affect me. Not to mention, I like a good argument.
You sound more like a 4w5 to me. I think our hesitancy to express ourselves has more to do with that intellectual side of us expecting perfect results for our efforts. When we don't think that's possible we hold off.