This is a version of the piston sand wave that works in 1.9. The version SethBling showcased worked on a bug that was fixed in 1.9. However, my design has each sand launching piston more spaced out (each launching piston in my design is spaced out 3 blocks from each other). It might be possible to make a design where each piston is closer together, but that would be more difficult.

Due to the way gravity affected blocks in Minecraft (Sand, Gravel, and Red Sand) work, the gravity affected block has to land before it is launched again. The reason for that is that if a gravity affected block is in entity form (in the air, non-solid) for too long, it turns into an item. Because it has to land, that means the piston sand wave has to be more complex.