Whoops!

Hi,
I have just realised that I have overlooked the fact that I can’t buy a JR pass from a station when I get to Japan. My threw teens and I arrive in Tokyo in 3 days.
My itinerary is:
Tokyo until 1.7
Travel to Osaka on 1.7
Travel to Hiroshima (day trip then back to Osaka) 3.7
Travel to Tokyo on 5.7
Travel to Narita airport 7.7

Q1: Am I too late to purchase a voucher for a JR pass or could I get it delivered to my hotel in Japan?
Q2: Is a JR pass the best option for my itinerary?

Many thanks
Lara