Bedtime for 9 week baby

My son was going to sleep every night around 21/22h since he was born (I went to sleep at the same time with him). But these last few days he suddenly is very very tired around 19/20h and falls asleep without barely eating something, which is difficult because then he’ll be up all night eating (until a few days ago he was eating pretty well during the evening and than waking up 1-2 times max during the night). Any tips ? Do I have to drastically change his bedtime hour? And when do YOU go to bed when your baby goes to bed earlier ?