The C sharp minor/major ninth chord is a 5-note chord consisting of the notes C#, E, G#, B# and D#.
You can see these notes highlighted in the interactive piano chart below.
The chord itself is often abbreviated as C#mM9.
Interactive piano diagram for the C sharp minor/major ninth chord
Chords that are a subset of C#mM9. These contain less notes but all of them are included in C#mM9.