Of COURSE the NCAA has defined "booster:
13.02.14
representative of Athletics
interests.
A “representative of the institution’s athletics interests”
is an individual, independent agency, corporate entity (e.g., apparel or equipment manufacturer) or other organization who is known (or who should have been known) by a member of the institution’s executive or athletics administration to:
(a) Have participated in or to be a member of an agency or organization promoting the institution’s intercollegiate athletics program;
(b) Have made financial contributions to the athletics department or to an athletics booster organization of that
institution;
(c) Be assisting or to have been requested (by the athletics department staff) to assist in the recruitment of prospective student-athletes;
(d) Be assisting or to have assisted in providing benefits to enrolled student-athletes or their families; or
(e) Have been involved otherwise in promoting the institution’s athletics program.
Basically, if you have ever worked for the Athletic Department or the Booster Club, ever donated to the booster club, ever assisted in recruiting or in providing benefits to student athletes (officially, not under the table) or the catchall category of "been involved otherwise in promoting the institution's athletic programs".
It is generally not enough to be a "fan", an alum, or a season ticket holder (unless you joined the booster club to buy your tickets), or even a former athlete. You have to actively promote the School's interest by either joining the booster club or somehow participating in recruiting.
If you recall, during the Cam Newton incident, MSU did not know whether Kenny Rogers was a booster or not. He was a former player, but there was no record of him him ever donating to the booster club, or assisting with recruiting. We "disassociated" him with a letter saying that we don't think he's a booster now, and he can never be a booster in the future.
Similarly, if you remember the Tee Martin deal, he was receiving money from a woman in Mobile who was a UT season ticket holder -- but she had never joined the booster club and was not considered a "booster" of Tennessee.
Conversely, when MSU got busted for Sherrill's stuff, one infraction was from an accountant in Hattiesburgh giving fake jobs to High School football players. He was an MSU grad, but he had USM season tickets and did the tax returns for all the USM coaches for free. He had once donated $100 to the Bulldog Club, and included on the subject line "NOT FOR FOOTBALL OR COACH JWS". But, thanks to that donation, he was a booster.
As for "the Driver", he is a booster if he has ever joined the booster club. He could also be considered a booster if he was giving these kids rides to camps with the knowledge of the coaches, but I doubt that could ever be proven.