If the kid is a liberal, then I hate him.
I know something of Mozart.
There is, in most music critique today, a tendency to embrace all sorts of touchy feely description that leans heavily on the words "texture" and "depth". Whereas texture means nothing, depth can mean at least something, and in the case of this young man the absence of depth translates in a straightforward way to very specifically an absence of anything but the primary theme.
There are no foundational instruments in this 9/11 piece doing anything whatsoever other than either echoing the primary theme or adding volume at a different octave.
Mozart's symphony number 1 was written at the age of 8 while travelling to London. Soon thereafter at age 11 he uncorked an avalanche of full concertos for the piano forte, younger that this new young man's age. The concertos were fully orchestral and already were showing his infinite capacity for perfect technique.
What I hear from this young man is an ability to write a tune for multiple instruments. He has a very long way to go and the comparison hype is undeserved. We'll know more in 5 years about what his prospects are. For now, we know he is no Mozart.