As of the date of this post, the time difference between Japan (Japanese Standard Time) and the U.S. west coast (Pacific Standard Time) is:
JST ----> PST: -16 hours
PST ----> JST: +16 hours
This means that at 09:00 (9am) JST, Saturday, it would be the following time/date in the U.S.:
EST: 20:00 (8pm) Friday
CST: 19:00 (7pm) Friday
MST: 18:00 (6pm) Friday
PST: 17:00 (5pm) Friday
*Note: For the sake of education, bear in mind that Japan does not recognize Daylight Savings, so during Daylight Savings Time (EDT, CDT, MDT, PDT) the time will be an additional hour:
JST: 09:00 (9am) Saturday
EDT: 19:00 (7pm) Friday
CDT: 18:00 (6pm) Friday
MDT: 17:00 (5pm) Friday
PDT: 16:00 (4pm) Friday