I have not read and I am not familiar with Brian Keene's book, "Ghoul," so with this review I am simply going off the content on the film itself, with no background foundations to base anything on. Strictly a review on the film, not a comparison.
For a film, the 2012 Gregory Wilson (The Girl Next Door, Home Invaders) directed effort, also titled,"Ghoul" was a damn good stab at a teenage horror flick. The story circles around a group of three friends in 1984 that have recently noticed first hand some disappearances in their town and eventually stumble across a murdered body.
Safe for a teenage and even pre-teen aged crowd, "Ghoul" was extremely reminiscent to the "Goosebumps" series that I was familiar with growing up and to be honest, I rather enjoyed even at this point in my life. Nothing out of the park scary, but nothing quite sugar coated and sheltered either, "Ghoul" provided me with a overall solid film for this genre.
Occasionally I believe the story came with way too much overboard drama, especially with Jacob Bila's character, Doug and the relationship with his mother and also Barry (Trevor Harker) and his father, none of which was officially resolved by the end of the film. The focus should have been entirely on the "Ghoul" for the length of the 80 minute film, instead of straying away for unnecessary dramatic purposes.
Overall I would give this movie a shot with your family, and as part of Chiller Films, you should be able to catch it on Chiller if you time it right. If not it's now available at your trusty Redbox kiosk.