Trying to skip anything mentioned above. Apologies for suggestions that wander too far afield! These are the books that popped into my head (if anyone can think of tragedy in these, please holler):
For modern sf/fantasy, my first thought was Skulduggery Pleasant, which is a delightful adventure that I think would hit the right age range, is engrossing, and it made me laugh a lot.
The City of Ember is a dystopian sf that I think would work in audio (I read it years ago).
The Lightning Thief is a really fun series. Quite funny. It has lots of mythological characters, but it’s definitely meant for a young reader.
A little younger is the Septimus Heap series, starting with Magyk, are kind of an ultra-whimsical Harry Potter. A lot of characters, but they are distinct.
For classic but “easy,” there’s “A Christmas Carol,” by Dickens. I think it’s absolutely charming.
I read and lovedThe Scarlet Pimpernel at that age, but I’m a little weird.
(It doesn’t fit this ask, I think, because I think it had a complex mythology, but The Weirdstone of Brisingamen would probably be a great fit for him to read on his own.)
The only thing I can think of that might be of interest to the OP are Bradbury’s “Something Wicked This Way Comes”, and Heinlein’s juveniles, like “Have Spacesuit, Will Travel” and “Podkayne of Mars”.
Here are some other assorted suggestions.
Science fiction classics? Radio programs “X Minus One” and “Dimension X” from archive.org.
More Bradbury: “The Martian Chronicles”, other SF and non-SF stories.
BTW -
I love the HHG radio shows, but the quality is very uneven, and they can be hard to understand. This first series is pretty great, but they go downhill after that.
FWIW my girl was listening and loving these when she was five. I have tons of students who read Redwall at eight.
This book is ridiculously good.
To each their own–but this was far and away my least favorite Chabon work.
Yes, definitely solid recommendation.
Okay, I’ve got my third-grader in the room. In addition to stuff I’ve already mentioned, she had one more recommendation: Hoot, by Carl Hiassen. There is some mild swearing, but it’s an eco-crime caper, and very funny.
I thoroughly enjoyed “Ocean at the End of the Lane” narrated by the author himself (Neil Gaiman). Might be a little scary, but if Rhythmdvl Jr. is reading the Hobbit I think it should be fine if I remember correctly. And Gaiman’s voice is fantastic.
Sorry - missed the edit window - on second thought, Ocean at the end of the Lane might have been more marketed for adults than I remember. I found a review that describes it as “Not just for adults, but not quite for children.” Maybe too much for an 8 year old. I’d suggest checking out plot synopsis on Wikipedia first before pressing play.
A website that can be really useful for figuring out age targets is https://www.commonsensemedia.org/. It’s really useful if you’re trying to avoid specific themes (or if, like me, you really hate gory movies). For example, for Charlotte’s Web (spoiled out of an abundance of caution):
Seconded for Skulduggery Pleasant. The audio version I heard was read by an Irish fellow with a pretty heavy accent, so, just a forewarning in case he has trouble with accents. Even if so, it’s a great series and should be enjoyed in some fashion.
Have you thought about podcasts? There’s one called The Radio Adventures of Eleanor Amplified that’s aimed for a younger audience; it’s styled like an old radio serial (think Flash Gordon), but very silly. There’s a road trip edition for it as well, the whole first series in a two-hour block.
1776, as seen through the eyes of Paul Revere’s horse. We didn’t hear the audiobook, but a teacher read it to us and every single kid in our class loved it.
The same author also wrote a book from the POV of Ben Franklin’s pet mouse, Ben and Me.
