First, his WMI is not remotely below average. That's actually the high end of the Average range. It's only low in relation to his extremely high VCI, VSI, FRI, and PSI.
Low WMI does not necessarily translate to poor reading skills. Among other things, it can also reflect dysregulated attention (e.g., ADHD), auditory processing weaknesses, emotional interference, or even seasonal allergies/medication for such.
The history you report of difficulty with following rules and ignoring questions, and frequent disciplinary incidents, suggests that, in addition to the cognitive assessment you had done, some additional investigation, probably beginning from the items I mentioned, might be in order.
