Folding 99 pre-flop for a raise

I've folded 99 twice in the past two weeks when two different early position players raised pre-flop. In both hands, the pre-flop raiser was a player who I had only seen raise pre-flop with premium hands (Group 1 & 2) and usually pairs. The players weren't necesarily good overall players but they were tight pre-flop as far as their raising standards. In the first hand, I was in middle position and everybody folded to me. In the second hand, there were two callers to me in the cutoff.


My dilemmna is this: Is folding 99 to "legitimate" early position raises a +EV play, especially with few callers? Or have I set my pre-flop standards too high/tight? I seem to have an arbitrary dividing line. I would almost always call with TT but have little problem mucking 99.


I've been thinking even more about this in the last couple days since reading a chapter in John Feeney's new book "Inside the Poker Mind" titled "Do You Pass the Ace-Queen Test?". In that chapter, John argues that cold-calling pre-flop raises with AQo (the bottom hand of Group 3) and worse hands is a sign of poor pre-flop play. John wants these kinds of players in his game.


With other pairs the decision is easy but 99 is in a murky middle-ground along with TT and 88.


So, how do you play 99 when an at-least-respectable player raises pre-flop from early position? Or even middle position with at least one limper ahead of him?