God uses leaders. I don't know if Cyrus was very spiritual, if he had a close relationship with God or not. It sounds like a possibility. The reason God used him in this way was because he was the leader of the world.
Do we pray for our president? We sure aren't encouraged to by modern media. Even though candidates are gearing up for the 2012 elections, Barak Obama is still our president and needs our prayers. God could use him. I don't know the president personally but from choices he has made, things he has said, he seems quite lost. He's a man desperate for prayer. He's a man in the most powerful position in the world, who could be used by God mightily. It won't happen if we don't pray for him.
I didn't vote for him and I won't vote for him in 2012. Yet, he is my president. If you are a U.S. citizen he's your president and he needs your prayers. The pressure in the position he is in must be so intense.
Whether you like him or not, whether you agree with him or not, pray for him. Pray for his family. Pray he commits his life to God and starts asking God what to do rather than other people.