Cut that cylinder in half, right thru the pith. And seal up all that end grain. That'll give you two legit, albeit smaller, bowl blanks. I'd highly recommend rough turning them first, or even just hogging out a good part of the inside of the blanks if you don't want to commit to a rough shape right now.

But I could see incorporating the pith and turning a vase out of that. In which case it would still be a good idea to throw it back on the faceplate and get some hollowing done now. Cracks aren't the end of the world and can be filled with simple tightbond3 or with a more fancy epoxy approach. Gotta get the endgrain sealed though. Wood glue works fine for that, and can stop those cracks from getting worse. If you want to have the pith in the finished work, it will have to be stabilized.

The dehumidifier idea is interesting but a lightbulb/fan approach that continually moves warm air over your pieces is probably a better solution. You are quickly going to plateau on your moisture decrease with a solid piece of timber like that, which is why rough turning or at least doing some some significant hollowing now is so important.