I gotta agree with BBC1 here that guys don't see any women signals. I'm a guy trust me i know we don't see signals i once had a girl like me for 2 years and i never knew it.
but don't wait for him for 90 minutes that may seem creepy to him to why you would do that. You should go there wish him luck then ask him to call you later or you ask for his phone number. Say that you wanna know how he did on the test as an excuse to exchange numbers. then you can take it from there.

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Life is too short so love the one ya got, 'cause you might get run over or you might get shot...
-Sublime (Thanks jslaughter )