Okay I forgot to tell about this earlier but here is a very useful glitch. It isn't actually triple jump because you do only two normal jumps but yeah I use that name here. Triple Jump is little harder to do than Double Jump. You need Glaives ability to do this, so it is only possible after Angor Rot boss battle.

So, here's how: Throw the boomerang and jump at the same time. Then if you get it right, you can jump again and move where you want to. Video with controller inputs: