The New Kids (1985) on Netflix

Abby McWilliams and her brother Loren are particularly normal teenagers. Their parents Mac and Mary Beth are killed in an accident. It's decided that Abby and Loren live in Glenby, Florida with their Aunt Fay and Uncle Charlie who own a gas station and an amusement park. Loren and Abby don't have much trouble making friends at their new high school. Loren starts dating Karen, the local sheriff's daughter while Abby starts dating Mark. Loren feels uncomfortable when he sees a blond-haired guy harassing Abby in the lunchroom. Mark tells Loren and Abby that the blond-haired guy is Eddie Dutra, a teenage drug addict who is the leader of a gang of redneck thugs. Loren helps Abby keep Dutra at a distance. Dutra's retaliations keep getting more vicious until Dutra forces a showdown at the amusement park by kidnapping Abby.