These left-hand rootless voicings add one note (to make three-note voicings) and provide richness with 9ths or 13ths. These third notes add harmonic and intervallic interest. For some common blues melodies, the 9th might sound wrong while the melody is playing. You can feel free to omit the 9th or replace it with the root of the chord if it sounds better to you. This example uses a simple form of the blues progression.
This example uses a more robust blues progression with some secondary dominant 7th chords added. Voicing the VI7, II7, and V7 with the same construction (each voicing moving each note down one half-step) provides smooth voicing leading and contrasting colors, dark to bright, emphasizing the blues sound.