Setouchi JR Pass

Hello :),

We are planning a trip from Osaka to Hiroshima, stopping in Onomichi, Imabari, Matsuhttps://www.jrpass.com/forum/using-the-japan-rail-pass/posts/new#yama, Takamatsu, Okayama, Himeji and back to Osaka

1) JR Pass Setouchi: is there an option for more than 7 days ? we will be there for 2 weeks.
If only for seven days - for which section would you recommend the Pass ?

2) JR Pass: A voucher is received at home then needs to be physically exchanged in Japan. After this, can the paper obtained be used to board trains directly or is it mandatory to obtain physical tickets for each train to be boarded (and go on the unreserved coaches)?

If the unreserved coaches are full, is it still possible to board the train and stand ?

I am thinking in particular for the train from Osaka to Hiroshima we may have to board last minute on 12th august in the evening (our flight from SH has a history of some delays.)

Thank you a lot for your help and expertise! Alex