This is pretty easily observable with baseball players as well. After playing thousands of games while standing in the same (relative) place on the field I/they can anticipate where the ball is going to go based on a variety of variables in real-time... instantly.
There is a very easy trick - you look forward in the distance keeping the balls in peripheral vision and there's 2 automatic reactions you have to develop:
1. when the ball going up is at the top of the curve - throw another ball up
2. when a falling ball goes out of your peripheral vision - do the "oh shit something's falling let's catch it" routine with the hand that has less balls in it.
Hands learn very quickly how to move to catch the balls that leave the peripheral vision "by itself" basing on the trajectory you've seen.
It's actually harder to juggle when you look at the balls directly, and it's impossible when you think about it and try to do the moves consciously because you're too slow.
It was mindblowing to me that it's easier to catch a ball when you don't look at it.
Which is why practice is important. You're essentially strengthening certain neural pathways with continuous exposure to certain inputs.
But this strength also makes us susceptible to misdirection and slight of hand.