The referendum was totally out of control. I will always condemn the violent response of the police that day, but the referendum was a total nonsense. You can easily find images of boxes left on the street and people "voting" without any control. And the counting (and whole organization) was done by those who wanted independence. You cannot trust those numbers.
There were regional elections on December 2017 and the independentist parties put together got 70 seats of 135 (less than the 72 they had before). More recently, in the elections for the national government this April, they only got 22 seats of 48 (some of the independentists refused to participate in Spanish elections after declaring independence, but turnout was still very high, more than 75%). The independentists never talk about these numbers, only the 90%. And I think that, many of them, seriously believe they are the 90%.