Note: I watched the anime, but did not read the manga.
In the Enies Lobby Arc, once the CP9 members return to Enies Lobby, Spandam gives a devil fruit to both Kaku and Kalifa.
Based on his childish and narcissistic attitude, I feel like he would want to eat them to be strong enough to do whatever he wanted. It seems out of character for him to give them both to someone, rather than use one of them himself. He loved having power over others, flaunting that power, and using it to cause pain to others. Was there an explanation I missed, or maybe the manga explained it somehow?