What is the name of a 70s or 80s animated movie,involving a stranded child on an alien planet with only a radio(which they convince him is alive,so he doesn't feel so alone) as contact to the people in the spaceship that are looking for him? I remember the quote "a feather against a mountain" was used in the movie.and at one point the child gets attacked by hundreds of wasp like creatures.

It's probably the French animated movie Time Masters.

https://www.askmehelpdesk.com/movies/animated-sci-fi-movie-boy-squirrel-earth-another-planet-94138.html?highlight=masters