Last nap vs bedtime

What time is your little one’s last nap of the day vs their bedtime?

My son will usually be napping when we pick him up from my mom’s around 3:30-4. His “bedtime” is between 8-9pm. He sometimes starts getting sleepy at like 7-7:30 but I don’t want to put him to bed that early otherwise he will probably be up at like 5am and we prefer he sleeps until about 6am when we start getting ready for work. I’m not sure if I should let him take maybe a 10-15 min nap at 7 or just try to keep him up?