The standard grips this chord is usually shown with.
Bm9 is B, D, F#, A and C#, a minor ninth. The shape this page opens on is written x20222, lowest string first.

Also written Bmin9, B-9 or B minor 9. The same chord either way; which spelling you meet depends on who wrote the chart.
There are 8 common shapes for Bm9 on the guitar, and 45 derived voicings in 5 families.
In which keys. Every note of Bm9 belongs to D major (the vi), F# minor (the iv), A major (the ii) and B minor (the i).
The common shapes, written lowest string first: x20222, x44435, xx4635, 75x675, x57677, 797779, 10-12-11-11-12-10, x-14-12-14-14-x.
Shell. Root, third and seventh: the guide tones fix the quality, so the fifth is dropped. That is what leaves a string free, so pick a tension to put on top. Bm9 has x2022x, 7576xx, x-14-12-14-14-x, x-x-9-7-10-9, 7x022x.
Drop 2. A close-position chord with the second voice from the top lowered an octave. Sits on four adjacent strings. Bm9 has x2022x, 5404xx, 7576xx, x-14-12-14-14-x, xx0425, x4743x, xx7637, x-x-9-7-10-9.
Drop 3. The third voice from the top lowered an octave. The dropped voice becomes the bass, which is why a string is skipped. Bm9 has 5x042x, x4x435, 7x763x, 9-x-9-7-10-x, x-14-x-14-14-10, 10-x-11-14-12-x, x-5-x-6-10-7, x-12-x-7-12-9.
Rootless. The root left to the bass player. Frees a finger for a tension. Bm9 has x4423x, xx0222, x5767x, xx7779, x-x-11-11-10-10, x-x-12-14-14-14, x4x232, xx4635.
Open string. An open string left ringing against a fretted grip. Because it costs no finger, it sounds a note the closed shape has none left for -- a tension on top, or a pedal root underneath. Either a familiar grip with open strings added, or a shape so sparse the open strings carry the chord. These belong to their key rather than to a shape, so D, A, G and E have many and Eb a handful. Bm9 has 757600, x44230, x57670, x00600, 5x0600, x00604.
Tensions. A shell of Bm9, root, third and seventh, leaves a string free, and the tones that belong over it are the 11 (E) and the 13 (G#).
The common shapes and the derived voicings come from different places, and both are explained in where the chords and the theory come from.
Shows each chord the way this style would voice it, and marks which of its alternatives belong to the idiom.