Complex sentence: The 2009--10 season was the club's first in the Conference Premier in which they finished 8th, 14 points short of the play-off zone, representing the first season in which the club had failed to make the top five in the league table.
Split into simpler sentences: The 2009--10 season was the club's first in the Conference Premier. This was the first season in which the club had failed to make the top five in the league table.