Bad Players when you don´t go up in next Level

I have occupied with my team the ninth place in the table.
So I did not go up.
But why did my players lose one star each in the same league?
This usually only loses when you move up to a higher division.

So that's completely illogical and penalized me in addition because I did not climb.

Well first sometimes the 9th and 10th goes up in league, you sure you are in same league level?
Second if your team had high stats you probably went up in league as well to prevent you from unbalancing the leagues.

exactly
You promote from 9th position