I call the Nine of Cups the “emotional miser” key. Arms folded in a stance of protection, the figure in this key guards the cups behind him jealously. Most Tarot books call the Nine of Cups the “wishes fulfilled” key, but usually for me, this key is about someone who is afraid or unwilling to share what s/he feels deeply.
When the Nine of Cups appears in a reading, usually the querent has a long-standing reason to be distrustful and seeks to protect him/herself from being so emotionally wounded again.
The hope I usually offer to the querent is that we grow and learn from every relationship, and we do not need to repeat the same patterns of behavior – we always have choice!