Nine
Nice! This kanji is the same as the radical that looks just like it (down to the meaning, even!). The radical is nine and the kanji is nine, making the meaning of this kanji really easy to remember as long as you know the radical first.
く, きゅう
ここの
None
Although this kanji has two on'yomi to learn, the pronunciations of those two on'yomi are very similar, so that should make them easier to remember.
When you were nine your favorite foods were cookies (く) and cucumbers (きゅう). Yum yum!