INFP 9w8 typing question

I have a question about the relationship between MBTI and enneagram because I’m not sure if my combination actually makes sense or if I’m mixing things that don’t really fit together.

I consider myself INFP because, after looking into cognitive functions, I feel like it’s the type that best matches the way I think and process things. However, when I discovered enneagram, the type I identified with the most was 9w8.

The thing is, I’ve seen many people say that an INFP 9w8 is a very unusual combination or even incompatible, and I’d like to understand why. I don’t know if there’s an actual contradiction between both systems or if it’s just based on certain stereotypes about how each type is supposed to be.

I’ve also considered that I might be ISFP, mainly because of the 9w8 combination. There are some aspects of my personality that make me question it, such as the fact that I’ve always been quite impulsive since I was young. I tend to act before thinking too much and I’m often guided more by what I feel in the moment rather than analyzing every possibility.

Even so, when I look at cognitive functions, I still feel like INFP fits me better. I know that being impulsive alone doesn’t define an MBTI type, but it’s something that makes me question my typing.