"Blue Nine" functioned as a pilot for the Resistance. Specifically, they were a part of Blue Squadron. Blue Nine took part in the Battle of Starkiller Base amidst the war between the Resistance and the First Order. In that battle, Ello Asty intervened to divert a missile, saving Blue Nine from two pursuing seekers.
The character Blue Nine is referenced within Ello Asty's Tales of Valor profile. This profile appears in Star Wars: On the Front Lines, a reference book from 2017 authored by Daniel Wallace.