What did Paul admit in Acts 26:9 about opposing Jesus of Nazareth?

Les explains that after Jesus of Nazareth began making inroads into Judaism, a religious fanatic concluded He had to be stamped out because He was ruining their culture and religion. Saul of Tarsus took the lead persecuting Jewish believers who had recognized Christ as their Messiah, doing everything he could to stamp them out. Les compares that pattern to communists, Hitler, and other despotic totalitarian leaders who get rid of opposition by putting them to death. Then Paul writes in Acts 26:9 that he verily thought with himself he ought to do many things contrary to the name of Jesus of Nazareth during His earthly ministry, which he also did in Jerusalem. He shut up many saints in prison—Jewish believers who had followed Christ in His earthly ministry—and received authority from the chief priests. When those believers were put to death, Les notes this proves the Jews had authority under the Roman Empire within their religion to put their own people to death, and Saul of Tarsus was at the head of it.