Boomerang caters more to popularity and less to overt nostalgia than it used to. Duck Dodgers is an established popular show, never mind that it only went off the air a little while ago; therefore, it is Duck Dodgers they broadcast.
His real name could be Porky Pig, but he just gets called Eager Young Space Cadet because that's what he is. In the military, soldiers are frequently referred to by their rank (soldier, private, sergeant, etc.), so his rank could be Space Cadet and so he gets called that, and the Eager Young is just added on.
Perhaps the adjective is a sub-ranking within the broader rank of Space Cadet... because it's in SPACE! You'd start out as a Hopeful Trainee at Space Academy, then advance to Wide-Eyed Young Space Cadet, Eager Young Space Cadet, Plucky Space Cadet, and so on up the ranks to Daring Captain, Intrepid Captain, and Dauntless Captain.) Aw, I Made Myself Sad now that Real Life military titles are so bland.
In the episode where Cadet touches Moognesiam and becomes a huge buff steroid fueled mass of muscle. I notice in one scene he rips his shirt off revealing two large nipple piercings. Does that mean that cadet actually wears giant nipple rings on a regular basis? This could go into nightmare fuel...
How this show ever got cancelled. Were the people in charge of Cartoon Network at the time afraid of money and/or success?
That would explain quite a bit...
Why did Hal Jordan take his Green Lantern uniform to the cleaners? It's pure energy generated from his ring. He could just will it clean.
It was dirty with yellow stuff?
You can bet he'll just will it clean from now on!
Speaking of the Green Lanterns...wouldn't most—if not all—of the members featured (looking at you, Hal Jordan!) have expired/retired long before the events of the episode, seeing as the show takes place in the distant future and not the 20th/21st centuries? Wouldn't it have made more sense to either use new Green Lantern characters, have Dodgers travel back in time to meet them, or have him meet the Legion of Superheroes (who are not only active in the distant future, but also travel through time) instead?
The Legion of Superheroes aren't one-tenth as well-known as the Green Lantern Corps, and using them would have sort of spoiled the joke — far as your average viewer were concerned, they could just as easily have been original characters invented for the show.
Using the Lantern Corps makes the jokey crossover a lot clearer, not to mention the space-based and alien-heavy Corps fits fairly well in the world of Duck Dodgers. And, well, for better or worse, Hal Jordan is the most iconic and recognized Green Lantern, so if they're going to do a crossover anyway, might as well get the main Green Lantern.
While they could have done a time-travel episode, that would have raised a few too many niggles, since Dodgers is already supposed to be from the past, and it would have added unnecessary complications. Besides — "Dodgers travels back in time and meets Green Lantern" is nowhere near as funny as "Dodgers happens to get his uniform clean at the same place as Hal Jordan."