Which route

Hi everyone,
My family and I (2 adults, two under 3 years old) are travelling and we want to do the following circuit by train (except fly when I wrote fly):
Option 1: Tokyo > Nagano > Kyoto > Hiroshima > fly back to Tokyo
Or
Option 2: Tokyo > fly to Hiroshima > Kyoto > Nagano > Tokyo

Which do you think makes the most sense? Do you have any alternative suggestions?

Also, all this in 9 days.
2 in Nagano
3 in Hiroshima
3 in Kyoto
1 rest day wherever
We don’t need any time in Tokyo.

Is this too ambitious? Would it make more sense cut something out?

Any advice would be super helpful! Thanks!