In one way Stirner was an acentrist, in another way, Stirner was an egocentrist.
Stirner was probably a subjectivist, certainly a value subjectivist and a relativist.
People and things are inherently nothing, or at most, pure potential, their kinesis is dependent on their interactions with other people and things, and the place they’re interacting with other people and things. There is no such thing as absolute, objective or universal kinesis. Consequently nothing can be said about the inherent qualities and quantities of people and things, perhaps they have no inherent qualities and quantities. There is no inherent value, there is no single valuer (God), there are many. Stirner was an egocentrist. Other possibilities are altrucentrism, objectcentrism, theocentrism, ethnocentrism, racentrism, acentrism and pancentrism and eyesinthedarkcentrism.