So I try to move the orbit of Saturn in our solar system with the planet editor... but it doesn't work...

And after testing many things, I realized that I can't move the following objects:

-Mercury
-Venus
-Earth
-Mars
-Jupiter
-Saturn
-Uranus
-Neptune
-Pluto

(I will refer to these as MVEMJSUNP)

However all other objects in the solar system can be affected. And every other objects in the universe can move.

Also there is something in the orbital parameters called "RefPlane". It should be on "Ecliptic" but for MVEMJSUNP it isnt and instead it's blank but I can change it to Ecliptic but it wont move those planets.

Please help? Is it because I need 0.9.9.0 (which I can't get because I have no means to get a private beta). If yes does any of you know when will it be released to the public? If not then what should I do?

What I found

 It should be on "Ecliptic" but for MVEMJSUNP it isnt and instead it's blank

It should be indeed "Ecliptic" in a standard 0980 version. Could you please attach your se.log file which is located in your SpaceEngine/system/ folder?
You didn't specify also if you did export the script of the planet in order to save your modifications, as manual says.
Modifications of existing catalog objects, usually contained in .pak files, need to be exported since SpaceEngine can read the contents of a .pak file but it can't write it back. 

So I try to move the orbit of Saturn in our solar system with the planet editor... but it doesn't work...

Are you using SE 0.980e?
Then this is because SpaceEngine does not use the 'Orbit' data for these objects, but the ephemerides from the 'DE436.pak' file.

If you extract the file 'SolarSys.sc' from the 'Catalogs0980.pak' archive into the 'data\catalogs\planets' folder and deactivate the parameter 'AnalyticModel  "Saturn-DE"' in the file, it should work for Saturn. (I have not tested it.)

How to deactivate?

How to deactivate?

Make two slashes before the parameter.

oh, I actually removed it completely xd (someone on the Discord told me) and it worked

I have same problem but with every object I cannot move any planet from its orbit my version 0.980.48 or latest jumbo update

Mention an object you can't move from its orbit in Editor. Is it a procedural object? What exactly is your goal, you want the change of orbit permanent? Because it's not possible to keep changes made with the editor unless you export the script and make it a modification to be placed into the addons folder, according the manual.