The Crab nebula pulsar was observed in 2009 January and December with a novel very fast optical photon counter , Iqueye , mounted at the ESO 3.5 m New Technology Telescope . Thanks to the exquisite quality of the Iqueye data , we computed accurate phase coherent timing solutions for the two observing runs and over the entire year 2009 . Our statistical uncertainty on the determination of the phase of the main pulse and the rotational period of the pulsar for short ( a few days ) time intervals are \approx 1 \mu s and \sim 0.5 ps , respectively . Comparison with the Jodrell Bank radio ephemerides shows that the optical pulse leads the radio one by \sim 240 \mu s in January and \sim 160 \mu s in December , in agreement with a number of other measurements performed after 1996 . A third-order polynomial fit adequately describes the spin-down for the 2009 January plus December optical observations . The phase noise is consistent with being Gaussian distributed with a dispersion \sigma of \approx 15 \mu s in most observations , in agreement with theoretical expectations for photon noise-induced phase variability .