Carica papaya in zone 9b

Hello, i recently planted some carica papaya seeds outdoors. They germinated, but I wanted to know if they would be fine during the winter. I live in northern italy, but thanks to a particular microclimate, temperatures during winter never drop below 26F. I have a few lemon trees, Phoenix canariensis palm trees and a dwarf cavendish banana. They all do fine (the musa loses its leaves, but sprouts back in spring without dying to the ground). Has anyone else had any experience with papayas in zone 9b?

You will need to protect it.
I also live in zone 9b, and it gets too cold here for the more delicate Citrus, like most limes. Lemons are more hardy, but about once in 10-20 years they will frost a bit. Similarly, oranges are fine most years, but occasionally there will be a minor amount of damage to the top leaves.
Musa will freeze to the ground and recover as you describe. I have one under covered patio. Plenty of air flow, just a little protection from the direct frost. Most years the leaves look pretty tattered and frosted by the end of winter.
Very few Avocado varieties will survive here.

In every climate zone there will be areas that are just a little colder in the winter, or a little milder. If you are in one of these 'banana belts' then you might be OK with Papaya outdoors, but I would build a shelter over them. Some arches and clear plastic would work very well. A botanical garden near me builds pretty sturdy frames of lumber and covers them with fresh plastic each fall.
If you can do that, I would also put Christmas tree lights in there to add just another degree or two of warmth.

Hi, I have built a structure around my papayas. Do you think that using bubblewrap would be sufficient? I have no sockets near the papayas so I won't be able to use Christmas lights. Would I need to water them during the winter?

Here is the reasoning behind tarping a plant:

Heat rises, cold settles.

Make a tent with air space around the plant. Open at the bottom, not tucked into the trunk, but touching the soil, and sealed there so cold air cannot blow in.
Arched, boxed or whatever needed so the plastic does not touch the leaves.
A dark mulch on the soil surface can help.

This will accumulate heat during the day the same way a car heats up when it is parked in the sun with the windows closed. Sunlight enters, but the energy is turned into heat.
The black mulch will soak up a lot of the heat, and warm the soil.

At night the heat will try to rise, but is trapped in the tent. It will gradually get cooler, but it may stay warm enough that the plant will survive. This is enough for plants that just need a couple of degrees of protection. According to one source Papayas may barely survive 29*F, but usually die.

I am not sure that this will be enough. Without some added heat (such as the Christmas light idea) I think Papaya is too tender to survive in our zones. Apparently they grow in zones that do not get freezing temps (35-40* min) such as the southern end of Florida.