That's it! Now you can enjoy the 1.9 pre-release. minecraft folder, and access the bin folder inside of it. jar file directly from the Minecraft server! Accept no substitutions! This is what you want.

If the video above made you interested, you can follow these directions (or skip ahead to a tutorial I found on YouTube) on how to install the Minecraft 1.9 pre-release yourself and give the new features a spin! These instructions are specifically for Windows folks, but the same principles apply for users who want to enjoy it on their Mac too! This guide is very similar to the one I produced for the 1.8 pre-release, so feel free to refer to those as well.