In bed at 9pm is normal for a 9 year old. There will always be people saying theirs are sound asleep as soon as their head hits the pillow at 6pm, but they are either also getting up at 4.30am or stretching the truth.
Ideally, the younger one should be in bed earlier, but they are also fitting in with you having a full time job - after all, most of us would find it difficult to go straight from work/gym/dinner to sleeping, especially if we only saw family members for an hour or so a day, even as adults, so expecting two children to be snoring by 7.30pm when they might have only seen you since 6pm is unrealistic.
There are some things you could do to try and calm the atmosphere down, assuming there aren't any SEN.
Set a time where things are quieter/calmer, say 7pm. From then on, you don't have the big lights on (as they keep many people very awake and alert) and there's no kids' TV going. Get the younger one bathed and in pyjamas, then sitting down with you. Off to bed at 8pm. Then 8-9pm is time to do the same with the eldest. Make sure there isn't light coming into the bedroom that could wake them up, no gadgets and no screaming, shouting or smacking if one does reappear.
Whilst you are tired, you're then able to go to bed after that point.