Cub cadet riding mower Mower Blade and shaft wiggle

I am not familiar with Cub Cadet but would suggest that if spindle is loose [wiggles] then one or more bearings need replacing. Remove the whole deck from the machine and turn over. Check the blade [s] are firm. If not undo the nut holding the blade on and remove the spindle and its housing from the deck frame. Remove the driving pulley also. Usually these types of drives have a spindle with a special fitting on the lower end for the blades to fit onto. Some are forged on the end of the spindle and the bearings come off the other end. Others will be removeable and so the bearings will come off each end. What ever, clean up with fuel and replace both bearings. You may have to remove the seals on the inside to let grease in. Make sure the top bearing has plenty of grease as it may miss out if all the grease goes down. Some machines it is better to leave the seals on top bearing. I have found that it does not pay to use the hose connection to clean the deck as the water destroys the bearings and only half cleans the deck. Best to put planks onto trailer or ute deck and run mower up so you can get underneath with big screw driver every now and then. Take blades off and sharpen them then also.