The Lord decides sainthood, not the Vatican.
It would seem that you are not familiar with the steps toward Sainthood in the Catholic Church. Am I correct?
First, a person is pronounced “Servant of God”
Second, a person pronounced “Venerable”
Third, a person is beatified “Blessed”
Fourth, a person is canonizd “Saint”
It takes two miracles to work through all this.
Yes, as Jesus judges each on our death and accepts us into Heaven as saints, or temporarily into Purgatory or into Hell.
In addition, Jesus gave the keys to the Kingdom of Heaven to Peter and his successors the authority to bind and loose. (Matthew 16:18-19). So the Pope has the infallible authority in matters of faith and morals to solemnly canonize an individual as a saint.