It looks to be months from the time that SpaceX claimed to have solved the problem that caused the vehicle loss of September 1 until the actual return to flight. There are stories to the effect that the delays are to convince others that the vehicle is safe. One problem is that piles of paperwork and man years of investigation is less convincing than a flying vehicle. I don’t know if SpaceX has solved their problem or not and people far more informed than I am don’t know for sure either.
A convincing argument would be several vehicles flying with no other entity worried about insurance or loss of payload. Production of the Falcon IX is supposedly able to support a flight rate much higher than current practice would suggest. But flying empty vehicles for no revenue is an incredible waste.
An orbital depot would sure be a handy bit of hardware to have in place about now. While many of us have suggested at various times that a rocket under development would be ideal for delivering propellant, relatively few have suggested the same thing as a pure confidence builder after a mishap.
If an upper stage had been modified for use as a propellant depot totally owned by SpaceX, it could have launched after the 2015 vehicle loss as a confidence builder and alternate destination in times of over supply of vehicles. Over supply could be both from over production and reused stages. The modified stage depot would not have to be as sophisticated as the ULA ACES as long as it was reasonably useful, and more importantly, in use.
It would seem that SpaceX could have launched a couple of tankers by now to build confidence after the September loss and followed it with revenue flights. Revenue flights sooner rather than later could possibly pay for the marginal cost of the confidence builder tankers. Payroll must be met either way, and little more red ink in one month to avoid several months of slightly less red ink per month could be a sound business decision.
I think most of us are already aware of the benefit of having 40-50 tons of propellant in LEO from the last three flights for use in a major mission to the GLAMs. (GEO, Luna, Asteroids, Mars)