Perhaps stoner googles it when high (9)
I believe the answer is:
geologist
'perhaps stoner' is the definition.
(a geologist studies stones)
'googles it when high' is the wordplay.
'when high' is an anagram indicator (letters get high or drunk).
'googles'+'it'='googlesit'
'googlesit' anagrammed gives 'GEOLOGIST'.
(Other definitions for geologist that I've seen before include "One studying rocks" , "One studying the earth's structure" , "Specialist in the earth's history recorded in rocks" , "Specialist in the history of the earth in rocks" , "Specialist in the physical history of the earth" .)