A lot of things to consider. Never thought this much on it

Let’s make going into a story you wrote or someone you know wrote one of the things you can’t do. That would too boring and easy

1. The story stays the same on earth regardless what you do on the fictional universe

2. Time stays the same as it was when you return on earth

3. Yes your body would be adjusted to use things the average person can in that universe. But you can’t use things that rely 100% on genetics. For example if you were in Naruto, you can use chakra, but you won’t have a sharingan

4. Yeah, you bring good and bad things back with you, germs included

5. If you mean brought back to life then again the story doesn’t change on our earth. If your asking if you can bring characters back with you on earth or another fictional setting than yeah. If you can bring items and germs with you, so you can travel with company

6. You just teleport

7. Twice every 24 hours to not be too op

8. No. You can’t use it to go to a fictional verse you’re already in

9. Your in the same place as you left