Until 31th of August, only a few shuttle bus is available besides Sat, Sun and holidays. It is below.
From Osaka station to HRO
(Mon - Fri)
18:00 19:00 20:00
(Sat,Sun and holidays)
09:00 10:00 11:00 12:00 13:00 14:00 15:00 16:00 1 7:00 18:00 19:00 20:00 21:00
From HRO to Osaka station
(Mon - Fri)
19:00 20:00 21:30
(Sat,Sun and holidays)
10:00 11:00 12:00 13:00 14:00 15:00 16:00 17:00 18 :00 19:00 20:00 21:00 22:00
It will be quite nice.