I recently tried to play Minecraft 1.9 for the first time, as I've only been playing modded 1.7 and 1.8 recently. However, I was greeted with some very strange glitchy visuals upon attempting to load up a world. I checked 1.8 after discovering this, and there are no such glitches. Both the 1.8 and 1.9 clients are unmodified. Below are some screenshots.