Is this an example of the ideology of Satanism?

I think that you are thinking too deeply into a fictional book. The "I solemnly swear I am up to no good" pact was about pranks and not Satanic rituals. In the pact, it doesn't say about doing anything 'forbidden.' In the story, there was a line between good and evil, and the protagonist was obviously a good character that showed no instances of devil worship or cult-following.