i know your desperation well! some kids just take longer. neither of mine started crawling before 11 months - and luke definitely wanted to be mobile before then. i think they come preprogrammed with a set time to start crawling, and when they hit that - they're off!
don't remember about jaina, but luke just starting pulling up at 13 months too, and no sign of walking yet. jaina walked at 15 months.
it will come!!!! until then you just do what you can with reaching, etc.