I don’t think there is an official Latin translation. I tried translating the English version into a few different Latin permutations and Googling, but didn’t turn up anything. I surmise that, like the Fatima Prayer (which was originally in Portuguese), there exists no “official” Latin version. Based on the style of the English translation of this particular novena, I think the original is likely in Italian due to some of the idioms.
Nonetheless, here is my Latin translation (using the Clementine Vulgate for Scriptural quotations):
I. O mi Iesu, dixisti: ‘Amen dico vobis, petite et dabitur vobis, quaerite et invenietis, pulsate et aperietur vobis.’ Ecce pulso, quaero et peto gratiam (name your request here) Pater noster… Ave Maria… Gloria Patri.
II. O mi Iesu, dixisti: ‘Amen dico vobis, si quid petieritis Patrem in nomine meo, dabit vobis.’ Ecce, in nomine tuo, peto Patrem gratiam (name your request here) Pater noster… Ave Maria… Gloria Patri.
III. O mi Iesu, dixisti: ‘Amen dico vobis, caelum et terra transibunt, verba autem mea non praeteribunt.’ Ecce, in verbis infallibilibus tuis consulatus (or consulata if female) sum, itaque nunc peto gratiam… (name your request here) Pater noster… Ave Maria… Gloria Patri.
O Sacrum Cor Iesu, quem non miserere infelicium impossibile est, miserere nostri miserabilium peccatorum et da nobis gratiam quam petimus te, per Dolorosum et Immaculatum Cor Mariae, Mater pia tua et nostra.
etc.