My iPhone connects to the Bose Audio head unit in what feels to be about 10-15 seconds after starting the car. Never actually timed it, but it does not feel any longer than that in my 2008.
Actually, you could try on your phone to forget that BT device and on the head unit to delete that paired phone and then run the pairing process again to see if that helps. I hear that sometimes this corrects anomalous behavior.
Hope that helps.
ZoomFive