Is your sweetie flighted?
The feather that has the damage is the first or second primary feather on his wing. You can tell by the shape of the feather that it's an outer wing feather. They are built slim and narrow because it's an impact feather meaning it takes quite a bit of abuse hitting things while flying. I do see where the right side has the barbs missing ( left side if you have the feather upside down like in your picture ). That would not concern me unless I started to see it on all the feathers and that is an unlikely spot to barber. The base while ruffled is normal too. They molt feathers because they get old and worn. An active playful macaw is going to do some abuse to feathers especially at that age.
When my scarlet was that age we used to say he looked like he was run over with a lawnmower twice.
All the feathers you have pictured are normal. I see no evidence of feather destruction behavior, just wear and tear on a young macaw.
The fee for putting your mind at ease is a picture of the whole bird.
Baby scarlet's are quite cute some of us need our baby picture fix.