well that’s not good at all as some of us really need the events plugin 
– I have also just confirmed that this is indeed the case. Hopefully someone will fix the issue asap.
My present install is on AWS on an Ubuntu ec2 with the standard install (Docker) … I know this has nothing to do with this issue but thought I would add it for clarification and remove hosting as a suspect.
I am now reverting back to 2.9.0.beta8 vs 2.9.0.beta9, tested on other environments, 2.9.0.beta8 and events plugin together allow image uploads through the Composer WYSIWYG again.