Based on how much top players are producing, I think something between 110 points and 115 points today is equal to 100 points in 2009. That's with looking at the point production leaders, but that also scales pretty decently well if you just look at increased goal production. But with that being said, McDavid putting up 150 points this year is still equal to about 135 points over a full season. That's better than what either Crosby or Ovechkin did at their best.
It's not as big of a difference as their raw production suggests, but McDavid is still clearly better.
That ratio would have 2009-2010 Crosby, who finished with 109 points, at about 123 points today, which seems believable to me.