If I am on the SITA bus from Positano arriving Sorrento at 8 AM, will I have enough time to make the Circumvesuviana Train departing Sorrento at 8:26 AM?
For sure; the buses and trains leave from the same transportation station hub. Sorrento is the beginning of the line for the Circumvesuviana that terminates in Naples
And the Circumvesuvia has many departures so if you miss one the next one will be along soon. About a one-block walk from SITA stop to train station.