I've got bad news: it is likely to the point of near certainty that several of our players use marijuana and/or other substances recreationally. Several also almost certainly did/do consume alcohol underage. No inside info re: the current team, but I knew several D1 basketball and football players at UIUC and elsewhere. Unless the culture has changed dramatically over the last decade (it hasn't), these guys work very hard 95% of the time and play very hard the other 5%.
I can 100% confirm this has been the case since the late 90s as well. I had direction interaction with the dealer and the players back then.
People need to get over the pot stigma. Alcohol causes more problems.