While I would prefer to avoid messy situations (blood/guts and/or legal pains in the arse), I assume my preferences don't matter if little fucker (gender neutrual) number 1 is:
1)IN MY HOUSE
2)IN THE MIDDLE OF THE NIGHT
3)WITHOUT MY PERMISSION OR A FREAKING INVITATION
If the situation permits, my wife dials 911 (phone on her side of bed) while I lock and load. While she is on the phone (so 911 operator can clearly hear), I verbally issue "Get the fuck out of my house NOW!" as many times as I can.
Somewhere in the process will also be "I have a gun and WILL shoot you".
Kid (I don't care if it is male, female, transgendered, or otherwise) has two choices. Choice number one moves his ass backwards towards the doorway and he can leave and live another day. Choice number two moves him in my direction towards me. Result of making this choice will be a couple of rounds sent his way. The decision will be all his as was entering my house in the first place.
Depending on the mood, I may issue "Get on the ground with your hands to your side" and I may attempt to hold him until local LEO arrives to cart him away.
My number one goal would be protection of my family. If he chooses to leave, then fine. Goal achieved. Subduing him would be all fine and cool, but not my top priority. Protecting my family and providing for their safety will be. Subduing him is a secondary goal and may not make the most sense.
Of course, this is the preferred situation. Most SHTF sceanarios are less than ideal. If I don't have the time/distance to make said decisions, then I will automatically 'fear for my safety' and the little fucker is getting fed lead for a midnight snack that night.
Will worry with sorting out the BS later.
I will countersue for cleaning up both the mess in my house as well as in my shorts as I will undoubtedly shit myself in the process.
Now, if junior has a friend (meaning more than one), that is a whole 'nother story. Fuck em if there is more than one.