Why are there only nine Ashrei's ? Is there a significance? Is there an allusion? How should the numbering be thought of?

What is the significance of the number 9? Is it even correct to say that there are only nine? Like isn’t the last one the ninth one and extension of the eighth one?

• is it wrong to think about the 10 words in the significance of 10 and falling short one?

• is it a forewarning of the loss of shabbat in the churches?