Answer:
I have a strong affection for belly buttons.
Man walks over, man walks under, in times of war he burns asunder. What is it?
I have no voice but I can teach you all there is to know. I have spines and hinges but I am not a door. Once I've told you all, I cannot tell you more. What am I?
I was was before was was was.
Everyone has me, but nobody can lose me. What am I?
What is 9 added to any number ending in 1