Wow - some tough topics lately.
To me, it would really depend on the circumstances. I would have to hear all the details. Isn't sentencing determined by the judge after a verdict has been reached anyway?
In my opinon, if the child is guilty and the details of the murder suggest that the child is extremely dangerous and harmful, etc, then they should be tried as an adult.
If the child reacted in defense or there was evidence that the child killed because they were abused or something like that, then it probably wouldn't be fair to try them as an adult.
IMO, children should be tried as adults in murder cases.
The punishment would depend on the circumstances, adult or child.