Phoenix is the same time as LA in winter, but 1 hour ahead in summer. Arizona doesn't observe DST, while California does. From March-November when LA is on PDT, Phoenix (MST) is 1 hour ahead. From November-March, they're the same.
This makes Phoenix unique - it aligns with Pacific Time in winter and Mountain Time offset in summer.
Check the season! In winter, no conversion needed. In summer, 9 AM Phoenix = 8 AM LA. Business hours still overlap well year-round.
Phoenix and LA are connected by 1-hour flights with American, Southwest, and United operating frequent service. It's a popular Southwest route.