Kids under weight for IBJJF division?

My kid is signed up for a bracket with his current weight but is within a pound of the max weight for that division, he's under 10 and going through a mini growth spurt. Will he get disqualified if I sign him up for the next weight bracket just to be safe and then he ends up weighing in at that lower bracket anyway?

I thought I saw somewhere that said "any weight over is disqualification, any weight under is okay" but can't remember if that was for IBJJF or a different competition's rules.