piano chord
G♯add9
G♯1B♯3D♯5A♯9
A major triad with a ninth added and no seventh — which is what tells it apart from a ninth chord.
Written the other way round it is A♭add9 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♯add9 is G♯, B♯, D♯ and A♯ — 1, 3, 5 and 9 counted from G♯.
On an instrument that cannot reach all 4, the 5 goes first, in that order.