He was accepted into SM in 2007 by SM Best Youth Contest when he was in the sixth grade, but the agency told him to come back after two years since he was too young. He returned after two years and began his life as an SM trainee.

Source: Kai Facts

Thank you sugenlover12 for answering the last question correctly ^^

Question 

What is Kai, Lay, and Sehun's powers? 

Answer 

Kai - Teleportation 

Lay - Healing

Sehun - Wind