Station is one cool dude, and the universes most excellent scientist, famed for making the 'good robot us's' (of Bill and Ted). He/they also play a mean set of bongos with the Wyld Stallyns...the question is, how long if at all did Station stay before returning to 'Heaven'?
In the Comic Series "Bill and Ted's Excellent Comic Book", Station appears repeatedly in the events following their Bogus Journey albeit not as a member of Wyld Stallyns which now consists of Bill, Ted, The babes and Phil (on bass).
Never fear, though! He does save the day when Joanna and Elizabeth get kidnapped in issue #5 and he appears in the 'final panel' of issue #12
In answer to your question, he returns to heaven almost immediately but then seems to be able to travel between heaven and Earth (various time periods) whenever the plot requires it.