The extended norms are not quite a completely different set of norms, since they require obtaining an 18 or 19 on the standard norms to be applicable, but yes, it is possible for scores on the low end of 19 to turn out a little lower on the ExNorms.
Given her age, if she received at least a few bonus points for speed, then she may well have obtained an 18 or 19. (But a nine year-old cannot obtain a 19 without bonus points.) The extended norms would be more relevant if she also scored well on the other subtest in this index (visual puzzles). We don't have enough information currently to determine whether the scores are an underestimate. You could call and ask about extended norms if you like, or just wait until the results come back, to see if they are warranted.
