 Born in Battle Creek, Michigan, Kool is a graduate of South Christian High School in Grand Rapids where he was a four-year letter winner in basketball, compiling a 71–7 record and winning the 2006 Mr. Basketball of Michigan award.He helped lead South Christian to Class B basketball state championships in 2003 and 2005 as a freshman and junior.Kool scored a Class B-record 43 points in the 2005 state championship game, 18 of which came in the fourth quarter.