So a new version of CoopDX came out called Pluto, and basically all it does is add the functionality of SM64 Saturn into CoopDX. However, there is a thing where you can jump-kick at full speed without holding back on the control stick. Does this make runs invalid?

Yeah thats the correct site. Under the mod site, remember to download Speedrun timer reworked. I think it's under utilities? and don't worry, it's fully legal in runs.