You need to upsize now before you get into the warmer months especially since you say the roots are coming out of the drain hole. You should trim any dead roots off and loosen the root ball. You can also plant it in the ground when your chance of frost is over and dig it up in the fall. I've done this many times with other tropicals. It looks large enough to fruit this year and by planting it in the ground, you give it plenty of room to do its deal. Super Dwarf Cavendish are very prone to choking when container grown and if it is ready to flower, you will lessen the chances of choking if it's in the ground.

Steve

According to http://www.bananalink.org.uk/how-bananas-are-grown , it l takes at least 2 months from flowering to picking ripe fruit.

It won't grow much in zone 5 ground before late July because the ground temperature lags the air temperature and the banana's meristem is under ground, too cold to grow much. Then there are only August and September to flower it and pick fruit. Suppose it begins to bloom just before the first frost arrives in October? The flower won't survive the transplant back into a pot. But, if you leave it potted outside, the meristem will be at air temperature or higher and the plant will begin actively growing in early June.

I would remove the sucker and repot both, a larger pot for the main plant and the same old pot for the sucker. It helps to water with warm water ~100 degrees F..

Id love a pup or sucker !! Is there a way to help a cloned super Dwarft banana to pup?

So if I get a super adwarft csvendish banana I'll have a better chance to grow pups? I've had a few cloned bananas , they never pup & die after they look great? I can't figure it out? I've tried so many times. Could it be there clones??? Help ? They grow great roots but plant always fails ? I keep under CFL 125 watt bulb 12 hrs. A day?