Should I buy a JR Pass?

Hi,

I will be going to Japan from Australia in April.
Is it worth buying a 14 day JR Pass?

My itinerary looks like this so far but I may miss out going Kokura if the wisteria is not blossoming :

9/4 Kansai Airport -> Wakayama
11/4 Wakayama -> Ryujin
12/4 Ryujin -> Shirahama
13/4 Shirahama -> Nachikatsuura
15/4 Nachikatsuura-> Okayama
16/4 Okayama-> Oboke (Iyaonsen)
17/4 Oboke ->Dogo Onsen
19/4 Dogo Onsen -> Miyajima BUT I will take High Speed Boat
20/4 Miyajima/Miyajimagauchi -> Kokura;
Kokura -> Kobe 21/4 Kobe -> Kansai Airport

Most of the trains are limited express with a few shinkansen..

I will be arriving at Kansai Airport on 9th April at 9.30pm.
I read that the Office at Kansai Airport closes at 11.00pm - do I have time to activate my JR Pass?
Where is the JR Office at the airport?

Your advice and help is greatly appreciated

Mary