If the equilibrium wage is $9/hour, so be it, but that doesn't justify not treating people like human beings. Telling them to show up early but not paying them for that time, micromanagement of bathroom breaks, unsafe or uncomfortable work conditions, not paying for being on call, etc. These aren't justified by labor market dynamics--it's indecent treatment of workers just because they have no other options.
From the linked article: "Though out of work, Rodriguez is surprisingly upbeat. 'The warehouses aren’t bad,' he tells me. 'If they treat people better and pay us what we’re owed, the work could be very good. It is honest work.'"