Clair de Lune by Debussy is in 9/8, but this bar doesn't look like 9/8 to me at all. Can anyone help?
It's "duolic", just 6 eighth notes to the bar where 9 would usually belong. You can see that 2 of the 1/8 notes (or one such note and a rest) fill the time one of the 3/8 notes does.
Just above the indicated bar, you see that Debussy uses duplets (marked explicitly there) instead of the equivalent 3/16 notes (dotted 8ths) for this piece. This is the same in the marked bar just that he doesn't bother to make this explicit. Basically, those are hemioles but played rather non-chalantly, keeping up the 9/8 meter with the 3/8 notes in the parallel line.