These 9% are representing a majority, since a lot of people didn't go to vote.
Considering both nominees have the highest disapproval rates I would say your statement is almost certainly incorrect. If anything, these 9% are representing a fundamental flaw in our first past the post system.
According to the statistic, 73 million did not vote in the primaries this year and about 88 million eligible adults do not vote at all. Add to that 103 million that are not eligible for voting. So if I'm not mistaken, only 18.5% voted in the primaries.
You mention they have the highest disapproval rates, but how is disapproval expressed if not by voting?