My trip plan

Day 1 to 6 Toky
Day 6 to 9 Kyoto (at 6th day we are starting to use our 7days JP Raill Pass for
DAy 9 to 10 Osaka
Day 10 to 11 Kobe
Day 11 to 12 Hiroshima
Day 12 to 13 Fukuoka (ferry to South Korea)

I would like to stay so long in Tokyo because we gonna buy just 7day Pass for trains, so we want to start using it for last 7 days.

Maybe you have any sugestions about the trip. Stay longer somewhere or not to stay for night somewhere?

Maybe there is something worth seeing on the way.

Thanks for any suggestions.

I think it looks good. But it is difficult to judge without knowing what your personal interests are.

Your current itinerary will give you lots of modern cities, and relatively little of traditional Japan (except Kyoto).

So I reccommend the itinerary below if you'd like more balanced itinerary.

Day 1 to 6 Osaka, Kyoto, Nara, Kobe, Himeji. They are all in single region.
Day 6 to 10 Tokyo (at 6th day you are starting to use our 7days JP Raill Pass
Day 11 to 12 Hiroshima
Day 12 to 13 Fukuoka (ferry to South Korea)