Your hypothetical scenario allows the sale of nine year old girls, while the bible doesn't condone it.I think we’re talking past each other a bit through neither of our own faults. I think, instead, it has something to do with the top-down, bird’s eye view our conversation has had so far on this bit of biblical doctrine. With your indulgence, I’ll try to trim back some of the giant squid’s arms and lay out a specific case study that might get us on more tractable footing.
First, I’ll stay away from any mention of slaves/servants. And I won’t set it in any specific historical era.
Imagine you are a nine-year-old girl in a Jewish family. Your father comes to you and tells you he has sold you to a millionaire, and that your new owner has come to collect you. Naturally, you are horrified and traumatized by the event, but eventually you get over all that. The millionaire provides you with comfortable lodging and furnishes all your basic needs: food, water, clothing, medical attention, etc., etc. The only work that is required of you is to do the laundry of the household and fetch the groceries at market. You are never abused nor even treated unpleasantly by your master and his family.
One day, a few years later, you meet a very nice young man at market and the two of you strike up a friendship. Your market schedules allow you to see each other on a regular basis and your friendship eventually blossoms into romantic love.
He himself is poor, but he has a steady job and earns enough to provide for a family. He asks you to marry him. You go back to the millionaire’s household and you explain to your master you would like to leave and go marry the young man. As nicely as he can, the millionaire simply forbids it. Maybe he lays out his reasons why or maybe he says you asking his reasons why is obstreperous and he is not obliged to tell you. Either way, he forbids you to leave.
In your opinion, does or does not the millionaire have clear authority for his actions based in scripture?
However, if you were a nine year old girl and had nothing to eat for a week, would you fret over going somewhere that had plenty to eat?
Would you do the laundry to continue to get fed on a steady basis?
As for the "boyfriend", he needs to supply a dowry to, again, gain ownership of the girl.
You should examine the cases that ARE in the bible that concern "servitude".
Like king Ahasuerus, to Mordeci and Esther.
Like Laban, to Jacob and Rachel.
Like Nebuchadnezzar to Daniel - (Belteshazzar), Hananiah,- (Shadrach), Mishael - (Meshach), and Azariah, - (Abednego).
Your view of servitude is jaded by the unGodly slavery of early America.
God would never advocate such slavery.