I think ± confidence interval should change with time.
I didn’t play enough 9x9 blitz back then and didn’t play it for very long time
I don’t believe these numbers. ± should be big
And what if someone like 35081 returns to OGS after long time? I think it would be better if they will need to play less number of games to change their rating - it may change a lot in long time, so ± needs to increase with time.