Form III Catechesis

Doctrinal teachings 

Who is God? Who am I? Who Are You? by Dee Pennock: This book covers many difficult topics for teens about living in the world. Some of us have used it in place of Charlotte Mason's Ourselves for citizenship. It has so many good quotes and comments free will and how to love our neighbor, all in the light of the Orthodox phronema. Encourage your students to get past the funny illustrations and really dig into this excellent text. Unfortunately, this book often goes out of print and can be hard to find. Check with your church school director to see if they may have copies of it you could borrow if you don't want to use the linked PDF.

The Way of a the Pilgrim and The Pilgrim Continues His Way (usually they are found in one volume rather than as two separate books), are classics of Orthodox spirituality. They follow the journey of a pre-revolutionary Russian pilgrim as he travels the land in search of advice on how to learn ceaseless prayer of the heart. Here's another review, if you want to know more.

Plan for reading the church fathers in Year 9 from Brandy Vencel.

Scripture 

Stories from Scripture by Arch. Vasilios Bakoyannis - Represents the spiritual truths of Holy Scripture in an accessible and applicable way.

Lives of the saints (be sure to also see the Biography section)

Among the Saints graphic novels (three books): Excellent graphic novels full of drama and suspense. These would be a great introduction for your Form III students if they have not yet read lives of the saints independently. 

Bearing the Saint by Donna Farley: A novel about a young fisherman's son who has an encounter with St. Cuthbert

The Orthodox Christian Church Through the Ages by Sophie Koloumzin (available on Archive.org) is a church history book, but it also has some biographies of saints included.

Praxis 

Letters to Saint Lydia by Melinda Johnson: It's a little difficult to categorize this one, but it's about a young woman whose family converts to Orthodoxy, leaving her with many questions. As she faces all the temptations of teenage life, she "pours out her troubles in letters to St. Lydia, who (invisibly to Lydia) answers, guiding her through her time of troubles with deep love and compassion" (from the publisher's website.)