Whether the movie deals with it directly onscreen or not, filmmaker David F. Sandberg and lead actor Zachary Levi talked a lot about trying to nail the abstract idea of a young boy with the "wisdom of Solomon" being the hero in Shazam!.
The superhero Shazam's name is actually an acronym, representing the sources of his powers and abilities: the wisdom of Solomon, the strength of Hercules, the stamina of Atlas, the power of Zeus, the courage of Achilles, and the speed of Mercury. While most of those are easily explained as regular, physical super powers, the wisdom of Solomon is one that does not present as obviously -- especially in stories, like the movie, where Billy remains fully in charge of the adult/superhero body rather than having another personality take over when he is a superhero.
"I asked this question with David at the camera test or maybe even right before it, I think," Levi told reporters during a recent set visit. "Having done the research on the character and being like, 'How is this going to work?' I think, if you've read the New 52, it does take a little license with that. In fact I don't think it's the only version of Captain Marvel or Shazam that's taken license with this kind of paradox, right? Essentially what was settled on is the idea that while some of these powers or these namesakes and powers, be it Hercules or Atlas or what have you, are a little bit more evident as Billy is becoming [Shazam.]"
Levi admitted that while it is something that fans will have to look for a little bit, Billy "does show his wisdom in certain areas throughout the movie, where you see him make a decisive move or he does something that you go, 'Oh that would be a wisdom of Solomon type of thing.'"
If you want a sense of how it might work, check out Geoff Johns's current Shazam! comics from DC. Not only did Johns write the miniseries on which the movie is largely based, but it shunts Billy into a leadership role among the Shazam Family, giving the character opportunities to display that wisdom without undercutting his youthful innocence.
Shazam! hits theaters on April 5, 2019. Other upcoming DC films include Joker on October 10, 2019, Birds of Prey (and the Fantabulous Emancipation of One Harley Quinn) on February 7, 2020, and Wonder Woman 1984 on June 5, 2020.