By sidling on the right side of the boulder that is on the front path after entering the cave, you can clip and run to the top of the boulder. From there you can either jump down to the chest or leaf to the other blocked chest. This way it is possible to get both small chests in that area without bombs. These chests are however not useful for 100%.
The Wizzrobe secret cave can be accessed using a combination of bomb boosting and leaf pumping. Line up with your back against the egg structure, and look at the island with the normal looking tree with rupees. Place down a bomb in front of you, then with a good timing backflip, pull the leaf, and hold the analog stick position in the direction Link is facing. The bomb will hit Link onto the egg, but then he will slide on it and get a jump. Proceed by leaf pumping to the island, then to the cave.