most card rooms i know have a rule where if your cards are exposed then you can only call or fold - in this case these are his only two options anyway and provided he didn't receive any help from the person he showed his hand to then i can see why the decision was made that way. If it was me though i'd warn the player that if he did it again he'd receive a penalty.
p.s. if i've got 9's and i'm short stacked, all in and my opponent is thinking about it and showing his cards to his next door neighbour - i'd want a call every time
