From what I was told by UA CSR that no minor should be seated alone. However I have proven this wrong: the CSR was able to put my 9 year old sitting on his own. She said the gate agent will override and will get us to be seated together.
I initially got 4 E+ seats with 2 UA S, then after 2 hours UA bumped us back to E-. My 4 seats was given to some other people, I called UA and got 2 good seats at E+ so I was ready to trade. We got no help from any FA and no one basically cared.
The kid of me kept flipping the bulkhead armrest during the flight and the mum next to him didn't bother. They were 3 people and I got a seat next to them as as soon as they saw me moved they immediately captured the seat to prevent me from moving back. That mum also changed her baby diaper inside the bassinet and she was doing big and small. The dad lifted the heavily soiled diaper up to try to find somewhere to dispose it and guest what - they didn't use the bathroom since (didn't even see the mum cleaning her hand using wet wipe). I smelled the brown stuff and extremely stale urine and it was just before the landing snack. FA went past saw the whole thing and I saw his month saying OMG so I didn't even bother complaining to them.