"He could've gotten the job"

1. He got the job.
2. He couldn't get the job.

Which interpretation is correct??
Are both interpretations correct??

See a translation

In conversation, I'd say "could have" is most often used when talking hypothetically about outcomes that were possible in a past situation, but didn't actually end up happening. For example:

"Why were you driving in such awful weather? You could've gotten into an accident!"
"Why didn't you ask me for help? We could've worked together to find a solution."

In the former sentence, the speaker is talking about a risk or danger that the listener put themselves in, while in the latter sentence, the speaker is talking about a different option that the listener could have taken, but didn't.

Another usage of "could have" is for when the speaker doesn't know what the outcome was, but is speculating about a possibility or just acknowledging that a certain outcome is possible. In this case, "could have" is to be taken more literally and used in much the same way as "might have" or "may have." For example:

"I don't really know why he moved to that city; he could've gotten a job there."
"I didn't see which way they went, but they could've gone towards the beach."

However, without any further context such as what's provided in the second sentence of each of the above examples, my first inclination would be to interpret the sentence "He could've gotten the job" to mean that he could've gotten the job, but didn't. Consider the following:

"You could've told the truth."
"He could've helped me."

In each of these sentences, I think most readers would be inclined to think that what is being suggested isn't what ended up happening.

So, to finally answer your question, I'd say your second interpretation is correct, while the first one is not. While the statement "He got the job" could certainly be factually true, the speaker doesn't go so far as to say with certainty that he did get the job, and instead only speculates about the possibility.