I was googling Andre De Grasse first races.
-As you can see, in 2011 he ran 12.28 in this race for his High School (Milliken Mills).
http://www.trackdatabase.com/viewresults.php?event_no=121¤t_meet=zzzz_db314
Then, another 2 races in 2011. 11.77 in the heats and 12.96 in the final (probably injured)
http://www.trackdatabase.com/viewresults.php?event_no=64¤t_meet=zzzz_db321
-In May 29, 2012, he ran 11.16 in the OFSAA Central Regional Track Championships. See the video. He runs with basketball clothes, and it's obvious that he hadn't experience coming out of the blocks.
-Also in 2012, June 7, he ran 10.62 (+2.6) in the OFSAA Track and Field Championships, and here he seems like another sprinter. Better start (Heck, here he jumped the gun I think!), decent acceleration, but not otherwordly top-end speed.
His HS coach was Tony Sharpe (Ben Johnson's teammate), who improved De Grasse in -at least- 1 second in only 1 year.
What is the limit for this kid?
Is he capable of a sub 9.80 legal? What was his training for the 100m/200m? He wasn't involved in 200m races in his H.S, at least not oficially.