Yes I am an official AC, and was introduced as Coach (first name).
Our high-school's do not allow parents helping.
I had to take all the testing, back ground checks ect. to be on staff
In that case I would ask the players address you as Coach XXXX, but do not get all bent out of shape if some of them don't. Most TB players know how to address coaches, but REC players are probably used to using first names.