Last year, on our first cruise, we got Palo ressies for 9:30 pm... which by the way, we loved... we grabbed something to eat around 7 pm anyway...just something light, and had no problem finding things to keep us busy on the ship while we waited to eat...
Even that late, and frankly to us, it didn't seem that late...it's not like waiting at home for dinner at 9:30... it was still worth it!!!
In case you were wondering, I believe we got out of there around 11-11:30.. the only drawback being that it was the same night as one of their midnight buffets AND WE WERE ALREADY STUFFED!!!!