It's certainly possible, but uncommon these days because the internet makes information on training and performance standards readily available. Thirty or 40 years ago, it was far more common as poorly trained and highly talent runners coming out of high school were common. Moreover, back then we heard rumors about some guy in California running sub 9, but it was never seen and was consider nearly impossible. Heck, back then the average state championship 2 mile in Michigan went down in 9:15-9:25 and some of those became All Americans.