I would barre E A and D with your index finger then use you're ring finger for D and you pinky for G. then when its 7,7,7 and 9,9,9 you already have the barre over those three strings so just lift up you ring finger and pinky, then
slide your index finger up to the 9th fret then put either you middle finger and ring finger on A and D or ring finger and pinky on A and D, which ever is most comfortable