The cultivation of piano playing as a competitive, athletic pursuit, an obstacle course requiring stamina and endurance, is bad for mind, body and music.
I sort of agree with this, if athleticism or competitiveness becomes the sole purpose of playing. However, certain pieces are truly athletic and present real physical challenges which must be overcome if you want to perform them properly.
What I always heard is that if your way of playing a piece causes any pain or discomfort whatsoever, even momentarily, even in very hard pieces, you are playing wrong. Usually pain and discomfort are a result of too much tension in the body, and you have to work on playing everything in as relaxed a manner as possible.
This I also think is basically true, and if you experience pain you really need to think twice before going on with whatever you were doing. Having said that, I think some discomfort and tension is inevitable when practising something very difficult that you have never done before.
In other words, I am not surprised that your hands get tired, and it's not necessarily the case that you are doing anything seriously wrong. But I think you need to be careful and don't rush your progress with these pieces.
With the fast repeated octaves in Scriabin, it should help to focus on one large arm movement for every group of octaves, so that the fast, small wrist movements needed for the individual octaves become sort of 'after-bounces' or recoils.
In the Revolutionary study, I would suggest practicing the left hand very softly. Just moving your fingers quickly will not make them tired, but playing every sixteenth note very loudly will do so for sure. Save the power for where its really needed.