Did Yamamoto Genryuusai use all his power aganist Aizen?
He did not use the bankai because he could not use it. 

His bankai Zanka no Tachi absorbs the flames of his Ryujin Jakka into the katana blade. During the battle in fake Karakura town, Wonderweiss absorbed his flames. Later when the flames sealed inside Wonderweiss's body are about to explode, Yamamoto has to shield it with his own body, which left his own body in tatters. It is reasonable to assume that he was either in no position to activate his bankai, or the bankai would not be strong enough since he couldn't absorb enough flames. 

If he had known Wonderweiss's abilities beforehand, he may have gone straight to his bankai from the start.