How should I blow up the switch at the top-right part of the room? I climbed the ladder and try to throw/kick a bomb, but none can reach it.

Hmm...trying to remember the room design...
Okay...I think I remember.
You have to use Ice Bombs to build a bridge.
You will most likely take hits though, so be ready.
And if you didnt know this yet, use Thunder Bombs to blow up those little pillar things.
Hope this helped.