What singer made appearances during Keith Urban's Ripcord World Tour who also the winner of the  fourth season of "American Idol"?
Ripcord World Tour The Ripcord World Tour (stylized as the ripCORD World Tour) was the eleventh concert tour by Australian singer Keith Urban. The tour was in support of his tenth studio album "Ripcord" (2016). The tour began on 2 June 2016 in Bonner Springs, Kansas and concluded on 17 December 2016 with two shows in Brisbane, Australia. Brett Eldredge, Maren Morris and Dallas Smith were supporting acts for Urban in North America. The Oceania leg of the tour was co-headlined with American singer Carrie Underwood, with Buchanan as opening act.
American Idol (season 8) The eighth season of "American Idol" premiered on January 13, 2009, and concluded on May 20, 2009. Judges Simon Cowell, Paula Abdul, and Randy Jackson continued to judge the show's contestants, along with Ryan Seacrest as host. The season introduced Kara DioGuardi as the fourth judge on the "Idol" panel. It was also Abdul's final season as a judge. Kris Allen, a native of Conway, Arkansas, was announced the winner of the competition on May 20, 2009, defeating runner-up Adam Lambert after nearly 100 million votes. Kris Allen is the only married winner of the competition at the time of his victory. This was the second season where both of the final two contestants had been in the bottom three or two at least once before the finale, with the first being season three.