There is time. They need to schedule their time, but the time is there. They can also still get to bed at a reasonable hour. If they take care of their business, they can get it all done and done well. There is no excuse beyond apathy for not doing so. Trust me.
As for class load, the first semester will typically see the football players taking 12 credits (three-four full-time classes). This is so they can still do their work at a high level while completing all of their football obligations. They will then take more classes in the spring, maybe 15 credits, and will usually take a summer class or two to make sure they will still be able to take 12 credits in the fall (since 12 credits a semester will not allow a student to graduate in four years).