I confess that I learned my ii/V/i different from most folks and will expect to get slapped around when school starts in a few weeks. I am not as well acquainted with the ii susb9 chord and don't follow Mark Levine's writing on it yet. But until then, I just use the modes approach.
If I start with a melodic minor scale (1 2 b3 4 5 6 7) as the i, and treat the ii as a mode of the same melodic minor scale, then the ii is (1 b2 b3 4 5 6 b7), which is equivalent to a m7b9 13 chord.
If I start with a harmonic minor scale (1 2 b3 4 5 b6 7) as the i, and treat the ii as a mode of the same harmonic minor scale scale, then the ii is (1 b2 b3 4 b5 6 b7), which is equivalent to a m7b5 b9 13 chord.
The difference between the melodic minor and harmonic minor is natural 6 vs b6. When you go from the first mode to the second mode (i-->ii), the 6th degree of the 1 mode becomes the 5th degree of the 2nd mode, so you get 5 and b5 respectively.
If I am wrong on this, please let me know (gently if possible).