I bought a book called “WONDER” which is Japanese edition to my eldest son today.
I’ve been wanting him to read this when he turns 10 years old as a main character of this book is also 10 years old.
Unfortunately, my son isn’t good at reading books. Therefore I thought he might show empathy with a main character if he turns same age as him.
He sometimes irritates to something because of the beginning of adolescence recently.
I hope he will get something important from this book.

I’ll try to read this in English edition. :)

Could you please correct my sentences?
Thank you 😊
Does this sound natural?

"I bought a book called “WONDER” which is Japanese edition to my eldest son today." =>
"I bought the Japanese version of a book called Wonder and gave it to my eldest son today."(This is the more natural version of the sentence you wrote. I think this idea might be better expressed as two sentences though. =>
"I bought a book called Wonder today. It's the Japanese version which I gave to my eldest son."
(Note: quotes aren't used around book titles in formal English. Italics are used instead; however, in everyday writing, feel free to use whichever.)

"I’ve been wanting him to read this when he turns 10 years old as a main character of this book is also 10 years old." (If there is only one main character in the book, you should change "a main character" to "the main character". Otherwise this sentence is fine.)

"Unfortunately, my son isn’t good at reading books."
(I suggest changing "isn't good" to "isn't very good" it's a softer way of saying this for people you care about. English speakers unconsciously do this to be nicer. It's like saying the person is not perfect which sounds nicer because no one is perfect.)

"Therefore I thought he might show empathy with a main character if he turns same age as him." =>
"Therefore, I thought he might empathise with the main character since he is the same age." (Sounds more natural.)

"He sometimes irritates to something because of the beginning of adolescence recently." =>
"He can sometimes irritate me because he is at the beginning of adolescence." (I think this is what you meant to say. Feel free to let me know. 日本語でも大丈夫です。）

"I hope he will get something important from this book." (Grammatically correct, but sounds a little stiff and disconnected from the last sentence.) Suggestion: "I hope he can learn something from the book that will help him grow."

"I’ll try to read this in English edition. :)"
(Was this apart of your sentences you wanted corrected? If so, try this sentence.) =>
"I want to try to read the English version."

I hope I could help. Feel free to ask any questions.