Nines and Fives are really different types- you could say they almost opposites in many ways. I tend to think you are a Nine. Here's why:
Many Nines mistaken type themselves as Fives (particularly if they are well-educated and intelligent). Fives rarely think they are Nines though. Nines often have a hard time typing themselves because they see a little of themselves in every type- it's because they are always trying to be recpetive to other people, to the point that they identify more with others than themselves.
Nines are easygoing, patient and accomodating. Fives are strong-minded and highly resistant to the influence of others. Nines like people and are trusting-sometimes too much so. Fives on the other hand, are suspicious of people and cynical.
Nines typically do not concern themselves with details, and they aren't usually good at following up once they have acted. By contrast, Fives are highly focused- love details, losing themselves in research. By contrast, even brilliant Nines tend to have problems concentrating; they also tend to lose interest quickly and to allow their attention to drift off.