Young Hollywood hits the red carpet at the iHeartRadio Music Awards where we catch up with stars like former "Dance Moms" stars Mackenzie Ziegler, JoJo Siwa, and Nia Sioux, boy bands CNCO and In Real Life, musician Jake Miller, "This Is Us" star Eris Baker, singer Johnny Orlando, and actor/singer Trevor Jackson! Find out which other celebs they're dying to meet!