At nine weeks? Yes they most certainly should be able to find a heartbeat. The heart starts beating at about five weeks gestation and the embryo is nearly an inch long - it would be hard for a trained tech to miss something that big. Unless your dates are somehow significantly off there's something more than a little weird about that. Did they try a vaginal ultrasound after not finding anything with the abdominal?
Its probably too early , my doctor said its usually better to do a ultrasound after 11 weeks