I had an 8:05 CP reservation, I was out the door by 8:45, so would have had no trouble making it to the meeting point. People seemed to be getting seated efficiently. I was in no way rushed, my DS and me had a great breakfast, and met all the characters. I didn't make multiple stops to the buffet. Maybe that would slow me down, but at that time of the morning my stomach can only manage so much, I still did pretty well though. My aim was to out before the park opened at 9:00. We stood at the rope drop at Cinderella's castle, and got mowed down by strollers and stressed Mom's trying to get to Dumbo, but that's completely off topic!!
So if it was my family, I could see no problem at all. However I guess it depends on how leisurely you like to eat breakfast.