Sorry, I read that as sarcasm.  Politeness is in short order here.  Yes, others have succeeded in having more than 8 persons in their families.  I don't have any families that large in my hood at the moment, but I have in the past and the mod works fine.  Double check to make sure it is enabled.   You can do that in game by typing ‘ShowConfig' in the cheat bar. 
Sometimes other mods work against each other.  If you have more than just AwesomeMod in your mods folder try temporarily removing all of them except AwesomeMod.  Check to see if the game works that way.  Then put your mods back one at a time, checking the game in-between each one to find which might be in conflict.
If you are still having problems, make sure you are up to date on your patches and the latest AM.  Than try typing ‘fixall' in the cheat bar. 

Hello! I'm trying to get enough information to help you.
Oh never mind, it is too late in the evening for me to give a crap.  I guess your neighborhood is just buggy.

Did you enable it in game through the cheat bar, or did you use the config tool?  If it is not set with the tool it will revert back to default settings each time you start the game.
http://www.moreawesomethanyou.com/ts3/awesome/config.php

Did the entire family move out, or just some members?  I know with the Goths in one of my games, Mortimer moved out with Bella when they got married, but Cornelia and Gunther already had another daughter who remained in the Manor, while in another game where Cornelia and Gunther didn't have other kids, Mortimer and Bella stayed in Goth Manor and had their own family there.  

I don't think the ancestral home concept keeps ALL family members on the lot, but should keep at least one to maintain the heritage.

If you make the household sacred, story progression leaves them alone.  They still go to work, and do other activities, but they won't get married, move, or do any other activities that story progression applies. 

If you are simply concerned about them moving, and not worried about other activities, I believe if you rename the lot to include the family name, then the lot becomes an ancestral home, and they won't be moved out of it.  As an example, look at the lot names for the Goth, Landgrabb and Alto families, the lots are named after them.  I am sure someone will correct me, and beat me about the head with a big stick if I have it wrong.