I'll answer every one of your questions with questions.
Overall: Who is your target audience? What point / message are you putting forth?
Is the video; art, entertainment, educational, marketing or something else.
Cut to the music? Yes & no - depends. Clip length - total length? Depends. Transitions? Yes & no.
Where to upload? If the target audience is kids on cell phones and don't know quality and doesn't even notice that it downgraded to 720 or lower for a quick stream, then youtube or tic toc. If your audience are professionals who views with desktops or quality laptops and demands quality, go Vimeo or other high-end streaming servers.
Trade seats with the viewer. Forget what you are showing, focus on what they are seeing.
Most people suffer from SAS: Short attention span. Just sayin.
I personally would have carefully picked the 6 to 10 very best clips with the most variety and cut them to 6 to 10 seconds to end up at about 1 minute. The vast majority of viewers will never see the end of an 8 or 9 minute video with little variety or story. Most people would see the end of your video if it was 1 or 2 minutes.
In entertainment, it's 'always leave them wanting more'.
In business, it's 'Show then what they need to be impressed and hire you'.
In film & TV, it's 'Cut out everything that doesn't drive the story forward'.
Bottom line; make the point and move on.
Some of this is cut to the music and some not. Some color graded and some not. Every project is different.
Examples:
Cinematic Reel to showcase completed Film & TV projects to Producers
Document a construction project for the Contractor:
More similar to what you did except - maybe lower quality video but I believe MIGHT holds attention a bit better:
Keep shooting, keep editing, keep creating.
I'm now better than any of my published work - and improving.