the reason for -ians is mostly the planet's name someone has given to it before noticing there are living beings on that planet (advanced radioastronomy). So the Acamarians from Star Trek are named after the planet Acamar which is an arbitrarily-chosen name for a planet long discovered before anyone flew there and found out about the alien race. In Star Trek itself everything is universally-translated anyway so if one speaks to an Acamarian and says the word "Acamar", it'll be autotranslated into Jhfatalak or how the planet is actually called in their mother language.
It's more pleasant to the eye and the tongue if you call it in a human-friendly way. Still you could name it Jhfatalak if you want to but it would hurt my eyes a bit. I mean what's wrong with Wolf 359 (the 359th planet an astronomer named Wolf discovered)? Why calling it p3o258 or Otilama like the indigeneous people call it?
If you want that much "realism" in terms of alien perception of the galaxy, you should also introduce the green color for our sun because it actually is shining green (max. intensitiy at green wavelength) and not white (the white color is just a misperception of our eyes). That however was rejected by tzlaine heavily