I'd say yes and no.
From KenPom's methodology page (my bad if this has been changed; there isn't an easy way to know if this is his latest post about it):
"AdjEM is the difference between a team’s offensive and defensive efficiency...It represents the number of points the team would be expected to outscore the average D-I team over 100 possessions"
By extension, AdjO is Pts/100 against an average defense.
However, shifting players from mid-majors to power conferences changes the median moreso than the mean, so it isn't ridiculous to compare across seasons. But it isn't perfect either, since what we really care about is how we perform against other top teams.