I have always understood the sons of god to be human in Gen 6 based on the rule of context (Gen 4:26)
However in Job 1 we would not know for certain whether he was talking about angels or men if it were not for Job 38 which is an additional reference by the same author using the same phrase which almost certainly is intended to be taken as angels rather than men.
4Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding.
5Who hath laid the measures thereof, if thou knowest? or who hath stretched the line upon it?
6Whereupon are the foundations thereof fastened? or who laid the corner stone thereof;
7When the morning stars sang together, and all the sons of God shouted for joy?
Now if God is asking Job where he was at the time of creation when He laid the foundations of the earth it seems that His main point is that
NO MAN was there. Therefore these sons of God shouting for Joy would be angels as would the morning stars doing the singing, unless he is referring to the creation of the stars when he mentions the morning stars sang together but even then it seems to be a poetic reference to the star representing angelic hosts themselves.
I don't think you can interpret Job 38:7 any other way than something God did in creation BEFORE he created Adam.
Would the same author use the phrase sons of god here as a reference to angels and use the same phrase in Job 1 to reference men? Probably not. It is not impossible bu I would assume he intended angels in both unless a language expert could present a good argument for differences in the Hebrew between these two references by the same author.
However Job applying the phrase sons of god to angels has never been a strong argument for applying it to Gen 6 while ignoring the context of Gen 4:26.