Pumpkin is moving at an approximate 100 meters per second. Unless Rindheart can earthbend at similar or faster speeds, the rock he's smashing with simply won't be able to make it there in time.

There's also to consider that Pumpkin is going at such breakneck speeds that he may as well land before Rindheart can even properly formulate and start excuting his plan. Though, that may not be true, as Pumpkin seems to be using the fie exhaust to slow himself down, which will still alter his trajectory and complicate calculations nevertheless.

On that note, landing 16 meters away after just missing a jump kick at 1/3 sound speed seems dubious to me as well. Depends on how much Pumpkin can slow himself down midair.

But yeah, those are just my thoughts; not an official judge ruling.