There's a plan that lets you jump higher. Maybe you need that? I'm not sure, I never figured it out myself, so I know you can beat the game without needing to get up there.
I figured that I wouldn't need to get up there to beat the game because I only encountered this in optional dungeons, but it would be nice.
Didn't know about the plan though. Will check to see if I have it and do what I have to to activate it.
Thanks.