Hello, Guys! Here is the question of mine: Is “David, who scored 500 goals, is a good player.” a definite relative clause?

It is a "non-defining relative clause."

Explanation:

When it comes to differentiating a defining relative clauses from a non-defining relative clause, it is important to consider whether the clause is "essential" or "not essential" to the meaning of the whole sentence.

If it is essential or extremely important, then it's a defining relative clause while if it's not essential, it's a non-defining relative clause.

In the sentence, "David, who scored 500 goals, is a good player." The clause here is "who scored 500 goals." If you remove this clause, the sentence goes like this: "David is a good player." This sentence still makes sense even if the clause was removed. Thus, it is a non-defining relative clause.

these have to be in your own words