DS slept in the very long car ride Xmas Eve, so I was able to push his bedtime back to 7ish (normal bedtime is 5:30). I put him down in a PNP in my aunt's room and had dinner, opened presents, then transferred him to the car seat at 10:30 when all was over. No one gave me any flack for it. There wouldn't have been anything for him to do during dinner anyway and we like to sit around the table for a long time at that particular gathering.
On Christmas, we went to a party at another aunt's house. I chose not to bring the PNP and got him to sleep in the Ergo instead around 6pm. We had dinner and planned to leave right after, but DS decided to wake up around 7:30 and be in a great, social mood, so he got passed around to a billion people while I hung out with cousins and friends I only see once or twice/year. We left around 9 and he fell asleep in the car.
DD's bedtime is no issue for holidays since she's a night owl.