I taught 9th graders (pre-confirmation) about 3 years ago. I was amazed at how little they knew. They weren't even familiar with the Gospel stories (and most of them couldn't read worth a darn, either!)
However, they were teachable. They were fascinated by the church history material I brought in, how the early Church were literally killing one another over the definitions in the Nicene Creed, and the loved they modern persecution stories from Voice of the Martyrs (especially when we sat on the floor in the dark to read about it), and they participated in prayer exercises with enthusiasm.
Today's teenagers aren't a loss by any means, but they need teachers who are passionate about the Faith and materials with some blood-and-guts and life-and-death emphasis.
i was baptized Greek Catholic, which meant i was confirmed simultaneously, so in 6th grade i had to sit out Confirmation, other than doing all the study prep stuff, in my Catholic grade school.