I a not sure I understand what you mean by "theory validation"
In any case, you may learn Politzer's part of the story from his Nobel lecture paper Politzer, H.D., 2005. The dilemma of attribution, International Journal of Modern Physics A 20(25), pp.5741-5751.
His advisor was the legendary Sidney Coleman, who was visiting Princeton from Harvard for a semester, Winter 1972-Spring 1973. Politzer visited him at Princeton a couple of times, and conferred with him and Gross. His unofficial mentor was Erick Weinberg, a more advanced graduate student with β - function experience. He worked independently, and was actually coming from a different direction: generalizing Coleman-Weinberg EW breaking to non-abelian gauge theories: he refocussed his discovery to the strong interactions himself. Unlike Gross & Wilczek, Politzer never wavered about the negative sign of that β - function.
If by validation you meant evidence in support, most theorists had accepted the point within the year of publication (1973), as described in Gross's and Politzer's recollections. The experimental results of DIS, etc were already at hand, so it was the interpretation and acceptance by theorists that was paramount at that stage. By year's end, it had been accepted as the enabling element of QCD, speculated about in 1972 by Gell-Mann, Bardeen and Fritzsch. Few theorists failed to instinctively connect asymptotic freedom to its obverse, infrared slavery, and arguments for confinement, proffered in 1974 by Wilson.
Experimentally, scaling violations predicted by it emerged convincingly in 1974. $e^+e^-$-collision jets were observed in 1975, and 3-jets in 1979 at PETRA. By that time there were hardly any doubters...