The stories come from André Arthur, who is a controversial figure all his own. However, despite the multiple derogatory stories and comments by Arthur, Therrien has never engaged in litigation with Arthur, as far as I know. So this leads me to believe that there is enough smoke for Therrien to know that he's created a fire and it's all coming home to roost. The bus driver story comes from a driver who had to put up with Therrien's antics as he sat in the first seat, directly across the driver, whenever the team he coached was being bussed. There is a source and Arthur can point to it, so Therrien would be hard pressed to be able to deny.
You also have to take into account that Therrien was an intimidating figure and even worked as a bouncer (there is a photo of him as a bouncer for Rock Voisine). And there are several stories that point to Therrien being disrespectful, arrogant and condescending from many sources, so none of this is out of character.
Makes you wonder what the hell is his obsession with flatulence. Although, I must say, I have witnessed this phenomena myself.
I was at the last game of a baseball season involving 12-year olds when after the game, the coach decides to remit trophies to each kid in recognition of their season. So, one by one, the kids walk up to the coach who is standing near the mound and I kid you not, as he would remit trophies, some of the kids were greeted with his loud farts. The guy thought the whole thing was funny but the parents were not amused. There are more Therriens out there than we will ever know.