Why compound times are not trated correctly?

If I set the time signature as 9/8, the program doesn’t treat the project as 3 beats per bar with 3 eighth notes each beat (compound time), but counts each eighth note as a part of a simple time instead (2 eighth notes each beat). So, the created bars are wrong in the grid, and the only way I could manage to fix it was setting the time signature as its simple equivalent (3/4) and set the grid to triplets.

I’ve seen this happens as well on Cakewalk, Cubase and Bitwig. So perhaps all DAW’s do this.

I would like to know: could anyone explain why all the DAW creators (including Audacity ones) decided to ignore compound times when setting the time signature?

Can anyone explain why all DAWs, including Audacity, ignore compound time signatures when setting the time signature, and instead treat 9/8 as simple time, counting each eighth note individually rather than grouping them correctly into three beats per bar with three eighth notes each beat?