What does Acts 9:30 mean?

The last recorded time a Christian teacher irritated the Greek-speaking Jews in Jerusalem, they killed him (Acts 7:54–60). The apostles are afraid Saul will face the same fate. He is a Hellenist Jew from Tarsus, the capital of the Roman province of Cilicia, but educated in Jerusalem by the famous Pharisee Gamaliel (Acts 22:3). For years, Saul zealously persecuted the church, but has since come to realize that Jesus of Nazareth is the Messiah promised in the Jewish Scriptures (Acts 9:1–19). Since then, he has doggedly proved his point, first in Damascus and now in Jerusalem (Acts 9:20, 28). Like in Damascus, some of the faithful Jews are less than receptive to his point of view and want to kill him (Acts 9:23, 29). Both the apostles and God (Acts 22:17–18) are telling him it's time to go.

While much of Saul's religious training was completed in Jerusalem, his hometown of Tarsus is known as a significant center of philosophy and academia; the teachers of both Augustus and Tiberius were from there. Tarsus is on the southeastern coast of modern-day Asia Minor, facing south into the Mediterranean. It's possible Saul converted his family at this point, as we know he was later on good terms with his sister's son (Acts 23:16–17).

There are several cities named "Caesarea" as naming a city after the Emperor was a good way to get into his graces. This one is Caesarea Maritima on the coast of Samaria and was dedicated by Herod the Great for Caesar Augustus. In AD 6, it became the home of the Roman procurators of Judea and Samaria. Since it is one of the few good ports in the district, it's a fairly easy sail up the coast to Tarsus. Later, Saul will be held there before going to Rome (Acts 23:31—26:32).