First time as PP's have said is probablly about 40-60 mins later. However, last trip a few rides that offered fast pass were not issuing tickets for the first few hours of operation.
Not all attractions will have FP open early, but
during many early mornings and AM EMH many (most) of the "biggie" attractions
should have their FP distribution open.
And, if you get a FP very early in the morning or AM EMH,
the earliest "return time" can often
be
within the EMH period.
Which attractions?
Expect to find the FP Distribution open on:
Expedition Everest, Kilimanjaro Safari (DAK)
Soarin', M:Space (Epcot)
Space Mtn., Peter Pan, Pooh, Buzz (MK)
Toy Story Midway Mania
and many times, Tower of Terror and Rock'n'RollerCoaster (DHS)