I'm in Northern Japan in Sendai. Whilst most of Sendai is 9a, a little further inland where we are in 8b. It gets very hot and humid here in Japan during summer so sometimes that is a limiting factor.
So far in our area, persimmons grow really well both the sweet kind and the astringent kind used for making hoshigaki (dried persimmon). I think
in the US you like to bake with the astringent kind?
Japanese plum/ume can do okay.
I've seen fig trees
doing well in our neighbourhood too.
Chestnuts do well too and i've seen hickory
nuts and Japanese walnuts too.
Yuzu is cold hardy so should
be okay. Goji and jujube is meant to be okay for the climate too.
I'm just a beginner gardener and only have a very small garden but I think i'm going to try fill it with a pomegranate tree and dwarf mulberry and goji then also raspberries, blackberries, gooseberries, haskap, cloudberries and golden berries. Will try strawberries too. Basically any berries that will grow since they are so expensive in Japan. Going to have a birds paradise! 😅
I'm also a Brit so going to experiment with Rhubarb. See if I can get it growing.