INFP 9
The INFP 9 often mistypes as a 4 when they are first introduced to the Enneagram. This is because the characteristics of the INFP and Type 4 share many of the same descriptors.

If someone has the INFP and the Tritype® of the 945, 946, or 947, this would happen naturally. The Tritype® that most commonly identifies with the INFP is the 945.

Once both systems are more fully understood, the 9 with the INFP has all of the 9 gifts and defenses of the 9. The gifts of type 9 are that they are: agreeable, open, gentle, accepting, allowing, kind, caring, quiet, loving, mediators that can see all points of view. The struggles of the 9 are: resistance, stubbornness, passivity, indifference, withdrawing, unresponsive, withholding, inaction, disinterest, and neglect.

The INFP personality type is often described as the mediator as well. So the INFP 9 is even more of a mediator than the type 9 with different MBTI. I find that the INFP 9 tends to be the introverted, kind, idealistic, creative, type 9 that has a drive to make the world a better place. This is especially true if the INFP 9 is the social/sexual 947 Tritype® or 937 Tritype®.

More on Tritype® here:
Katherine created a test that has been programmed to pick up particular patterns that the types use.
Take the Test here: https://enneagramtritypetest.com
General Information: www.katherinefauvre.com/tritype
YouTube: Katherine Fauvre | Creator of Tritype®