You need two weeks to do all of this. Basing in Gimmelwald for “a few nights” does not give you easy access except perhaps to the waterfall hike you want to do in Lauterbrunnen. The Jungfraujoch trip seems close but it is a bit complicated when you stay in Gimmelwald as it takes a few more steps — and time — to get there. (BTW, what hike, exactly, do you mean by “waterfall hike?”)
If you land in Zurich, proceed to Chur, spend the night, then take the Glacier Express route (not necessarily the panoramic train) to Zermatt takes an entire day and that puts you far from most of your other desired stops.
You have 5 major activities/locations that are more-or-less daytrippable from the Lauterbrunnen area: Aare Gorge, Jungfraujoch, Brienz to Interlaken, Kandersteg, Grindelwald plus a “waterfall walk” and a visit to Gimmelwald. That alone is 5 days of things to do in one small area. Travel times can be long, i.e., 1.5 hours, roughly, each way from Lauterbrunnen to Kandersteg. Remember, the weather may not cooperate and those who move through too quickly are often disappointed when the ONE DAY they have is raining.
As travel4fun said, you need to look at travel times realistically. You do not want to be moving after only one or two nights in a location as you lose so much of the time you could be enjoying a location and doing something. I would pick two locations at most: if you only have 9 days Perhaps the Lauterbrunnen area as one base and Montreux OR Zermatt as another.
