What is true of it
G♭m9 is G♭, B♭♭, D♭, F♭ and A♭ — 1, b3, 5, b7 and 9 counted from G♭.
B♭♭ is a double flat, and it has to be: every letter from G♭ upwards is used once, so the b3 cannot be written any other way.
On an instrument that cannot reach all 5, the 5 and 1 go first, in that order.
The easiest of the 1 fingering below is b9cb: 4 fingers, held at the 9th fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
It leaves out the 5. 4 strings cannot carry 5 notes, and the 5 is the one this chord can lose without changing what it is.
Where its notes are on the neck
The brass dots are G♭, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
G♭m9/B♭♭
2440
G♭m9/D♭
6440
G♭m9/F♭
x440
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.