Yes, Hirayama played in the AFC Champions League. He was part of the Urawa Red Diamonds team that won the 2007 AFC Champions League. The Red Diamonds beat Al-Ittihad of Saudi Arabia 1-0 in the final. Hirayama played in all six of the Red Diamonds' games in the tournament.
Kicking it with Sōta Hirayama: A Quiz on the Japanese Football Sensation