I don't know of anyone (including P. Kyrill's) whose comments are treated like they are setting Church doctrines, except for maybe a medieval Pope. Even with Luther, there is a mix because his writings on some topics like Sola Scriptura are going to be treated as pretty foundational, but when Luther talks on some other topics, such as expressing anti-Semitism, most Lutherans are going to treat them as Luther's private ideas.
If one wanted to try to make an argument in support of Pat. Kyrill's comments, they could see how Pat. Kyrill was talking about self-sacrifice, laying one's life for others. It reminds me of John 15:13 "Greater love hath no man than this, that a man lay down his life for his friends.") One can also notice Luke 7 (47. "Wherefore I say unto thee, Her sins, which are many, are forgiven; for she loved much: but to whom little is forgiven, the same loveth little. 48. And he said unto her, Thy sins are forgiven.") I don't think that Pat. Kyrill was trying to make an absolute blanket statement about anyone of any religion who dies in wars for any reason, regardless of motivation, etc.
Orthodoxy also has an attitude that we don't know the specifics of how God will judge every person. There is more doubt than in some other groups about the status of a person who just believed the doctrinal postulates of Christianity but never actually tried to follow them vs. someone who didn't believe in the right religion or sect but who followed Christian principles correctly otherwise.