I'm looking for a hack with which you can spawn holograms
There's no hack to do this. But you can create a hologram with a command generator:
https://minecraftcommand.science/de/hologram-generator
Creative mode required or survival mode?
Have a look at YT at Garkolym, he once programmed something like that. (Is in the 1.8)
Creative
Yes, but he no longer provides any download links
Have a look at Garkolym on youtube, at that time he published a client with which that works
I checked it out, unfortunately I no longer have any original files. Maybe someone else happens to still have the files