Baptismal Class
One of the ways that pastors can get involved at the school is by having baptismal classes. Whether they are pre-baptismal studies or studies that immediately lead to baptisms, parents will appreciate their kids getting their hearts prepared and dedicated to Jesus Christ.
Looking for materials to use? Steve Case is the author of the wonderful book, "It's My Choice." This book covers fundamental Adventist concepts that can kickstart conversations or be the basis for activities the pastor can invent. It is designed for ages 10–12 but can be adjusted for other ages too; the conversations can go as deep as the kids desire to, accordingly. There is also a teacher's manual that helps prepare the pastor to teach in an interactive and well-informed way. The best part of these lesson studies is that they are evangelistic. There is a part for parent interaction, so the baptismal lessons can travel home, creating opportunities for the Holy Spirit to work on the parents as well.
Also, check out "Partnering in the Mission: Pastor and Teacher Resource Manual." It goes into great detail in this area of evangelism, and the Baptismal Classes section can be found on pages 71–73.