IIRC Aerobatics are defined as more than 90 degrees of pitch or bank angle. Therefore a barrel roll is an aerobatic manoeuvre.
I have only seen a couple of frames of the alleged barrel roll, in online newspapers, and not the full sequence. Are the weather conditions, ambient lighting, and positioning of the aircraft in the sequence of frames, correct for the whole thing being shot from the ground on that date/time?
I have no idea of the height, speed or track of the aircraft at the time.