Blues typically follows a 12 bar pattern based around Dominant 7th Chords:
||: E7 | A7 | E7 | E7 | A7 | A7 | E7 | E7 | B7 | A7 | E7 | B7 :||
9th Chords use these degrees of the major scale: 1, 3, 5, b7
E9 uses these notes: E, G#, B, D
Mix up today's chord of the day with previous Blues guitar chords when you play through the 12 bar progression and tune in tomorrow for another guitar chord of the day.