You've received great advice above. Online study aids such as Cliff Notes and spark notes may also help a parent pre-screen a book for content.
Cliff Notes summary of
Ivanhoe.
Cliff Notes summary of
Great Gatsby.
Cliff Notes summary of
Jane Eyre.
Spark Notes summary of
The Lady With the Dog.
Spark Notes summary of
The Waves.
enotes summary of
The Bear and Spark Notes summary of
The Bear.
Cliff Notes summary of
As I Lay Dying. This book may be disturbing for a nine-year-old... and may require a lot of guiding conversation with a parent.