Well, in 9/8 time, the eighth note is worth one beat, and there are nine beats per measure. Now is the rectangle with the dot next to it sitting on the third line, or dangling form the fourth?
Sounds to me like 9/8 most likely divides into 3 groups of three quavers or 3 beats per bar.
A standard Crotchet rest with a dot (which adds half to the duration) will equal one group of 3 quavers i.e. 1 beat. The Box reffered to be a minim rest with a dot (which as we know adds half to the duration) which would equal two groups of 3 quavers or two beats.