Update at 10th
As severe rain in western Japan,
88house is safe and city center is ok in Hiroshima,
Access to 88house from JR Hiroshima station by bus or taxi is available as usual
It will be no problem to sightseeing in main destinations.
(Peace memorial park & Miyajima)
However some of area in the surburb have severe damaged.
・Sinkansen(Bullet train)is OK(from Osaka to Hiroshima and to Hakata to Kagoshima)
・To Miyajima Local JR line from Hiroshima to Miyajimaguchi is OK
More info in West JR http://www.westjr.co.jp/global/en/
・Sanyo highway from Onomichi to Hiroshima has been stopping.
1 week will need to fix the road.（will be 17th）
more info in Japanese
Access to Hiroshima Airport
Between Hiroshima to Higashi-Hiroshima station by Shinkansen(Bullet train)
Then Shuttle bus is available between Higashi-Hiroshima station to Hiroshima Airport.
It takes about 80minutes depend on road condition.
It might be better to start Hiroshima station at least 2 hours before the time you need to arrive at the airport.
Link in Japanase
If you need more information, Let me know.