Different things work for different people, but for many I think it's a mistake to run artifically slow. The mechanics at that pace are substantially different from what you'd be using even in a longer race. And for me at least it always felt terrible, very awkward and uncomfortable.
Two suggestions for your easy days:
1) Do some kind of alternate aerobic exercise. If you run really slow, that 8:30-9:00 pace is not really going to have much carryover to your "normal" running anyway--so you really don't need to worry about the nonspecificity of other aerobic work: elliptical, swimming, water running, bike, row, whatever.
AND/OR
2) Go at your natural "feels easy" gear, but insert walking breaks. Yeah, yeah, I know: "Gallowalking! The horror!" If you feel guilty while walking a minute or two after 5-10 minutes of running (on what's supposed to be an easy/recovery day, remember), you can add in some kind of calisthenics during the breaks.
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Personal note re the second option: Day after my first marathon I went out for an easy run--and found I *could not* run slower than marathon pace. But I wanted an easy day--just some recovery! I didn't fight the pace; instead I walked a bit after every mile or so. Worked out great, and gave me just the recovery I'd been after.