I just tried this squash this past season. Loved it! Mine was slightly overcooked but really liked the variety. Such a beautiful color and shape.
I used to regularly go to a Vegan Vietnamese place back in Renton, they had a lovely Pumpkin and Lotus Bean soup. They typically used the kabocha squash. The squash is in cubes in a clear broth. Didn't find a great recipe (most I found were not vegan, easy to find pork based recipes) but this video shows a similar soup with only a small pork addition which could easily be edited out:
https://www.instagram.com/reel/CtGa8X7utle/
Since mine was a just a tad overcooked, I could envision it further blended down into a creamy type soup. I would probably keep in the Asian flavors and use coconut milk.
Or -- with plenty of squash, you could do the pumpkin soup in a pumpkin like Martha Stewart!
https://www.food.com/recipe/martha-s...-pumpkin-13557