Ah, Level 9... here's a good enough walkthrough. I have a trophy so you can trust me enough
1. You start off on a platform with a little bit of water underneath and the floor is lined with spikes. This level requires you to be nimble and quick, so I hope you fill both of those qualities.
2. Jump left off the platform to the other edge that is filled with a little water. Climb up to the dry terrain and launch the arrow. Now QUICK QUICK QUICK!
Jump up the platforms and then on to the ladder before they are destroyed!
3. Hop on the ladder and then use the wooden crate to bounce your way to the other piece of land on the other side. Do the same with the next wooden crate and get yourself on the first ladder. Jump from ladder to ladder until you reach the other side. Break the create that is holding back the boulder and let it break the platform you're standing on and bring the other boulder down too.
4. Jump after the boulders and then ON to the boulder. Now set yourself in a position so you can move one of the boulders, mainly the one on the higher ledge. Push it so that it breaks away the spikes that was on that ledge, jump on boulder, and get to the top of the platform right above.
5. Crawl under the piece of terrain in that small room, grab the treasure, hope back on the terrain you just crawled under, and push the boulder off it. Jump after the boulder.
6. Land on the boulder, jump to the platform, and climb down the ladder. Jump from the ladder and launch the arrow, and then land in a safe area of water, mainly a deep one so you don't get killed by the spikes.
7. Submerge down the passage, collect the treasure at the bottom room, swim back up, get the rest of the treasure, and then go through the door. Congratulations- you won!
BONUS:
Gem: Unknown.
Life Crate: None