9/8 against 3/4

In 3/4 time, how do I temporarily notate 9/8 one one staff only?

After a while it goes back to 3/4.

It is not polymeter(?), since the music in “9/8” is 3/4 in still value

Using Alt+Return results in un-aligned music.


Probably the most linked to article in this forum:

Thank you.