Itinerary: Kyoto - Kobe - Osaka

We are staying 8 nights in Japan in early December and thinking to split our time between Kyoto, Kobe and Osaka.

Would it be worthwhile buying a JR Pass?

Can anyone give us some suggestions about our plan? Thanks!

Sat 8 Dec: Arrive 4:45 Kansai A/P. Stay in Kyoto.

Sun 9 Dec: Kyoto – Explore Arashiyama
Mon 10 Dec: Kyoto – Fushimi Inari-taisha.

Tue 11 Dec: Kyoto -> Kobe. Drop off luggage in the hotel in AM. Day trip to Arima.
Wed 12 Dec: Stay in Kobe. Day trip to Himeji. (Possibly do Arima instead and Himeji the day before?)

Thu 13 Dec: Kobe -> Osaka.
Fri 14 Dec: Osaka. Osaka castle.
Sat 15 Dec: Osaka. Shopping Dotonbori.
Sun 16 Dec: 2:20pm Depart Kansai A/P

JR pass not worth it.

I think your itinerary looks good. You will lose money with JR pass, so I recommed to check the JR regional passes for Kansai, at the for the travel between Kyoto-Kobe-Himeji-Osaka. You could do Osaka in one day, visit the Castle in the morning, and Dotonbori in the afternoon, and even at night, since Osaka never sleeps. Therefore I would recommend to go to Nara instead of doing Osaka 2nd day.

I hope you enjoy Japan and the Kansai region!

I forgot to say, you can buy at the airport the ICOCA + HARUKA pass, it's a discount only in Kansai and at the airport. With ICOCA you can go on subways/trains/buses (but doesn't work on the Shinkansen), and the HARUKA is a train serving only the airport and cities within Kansai (Tennoji, Shin-Osaka, Kyoto).
Then you could use a JR regional pass for going in between cities.

For the day trip to Himeji, you don't need the full day, half day is enough. The other half use it for Kobe. There is the Chinatown, the Ropeway to see the city, the Sake Breweries you must visit, the museums and the harbor.

For the last day in Kyoto, are you planning to visit Inari only? Since it's nearby, visit the Tofukuji. Not far there is Kyoto's stunning Pagoda and Kyoto tower. You should also stroll around Nishiki market and Gion.

Enjoy!

I would like to correct @catiasmteixeira, rather than get the ICOCA + HARUKA pass, I would consider the Kansai one pass + HARUKA pass, the Kansai one pass is a ICOCA IC card, but includes discounts and free gifts if shown to various establishments and services. you can visit the site to pre-order the card, and pay when you collect at the airport.