The notes of G7#9 are G, B, D, F and A#. G is the root, B the major third, D the fifth, F the minor seventh and A# the sharp ninth. Said aloud, its notes are G, B, D, F and A sharp.
String by string, low to high, it plays G, B, F and A#. This shape leaves out D, the fifth. It runs from G on string 5 up to A# on string 2.
G7#9 uses no barre and no open strings, so you can slide the shape up the neck without changing fingers. Strings 6 and 1 stay silent. Your hand covers three frets, from 9 to 11. There is one more position, starting at fret 2.
G7#9 and Em have G and B in common.
The notes of G7#9 do not fit together in any major or natural minor scale.