Should it not also depend on whether or not he is convicted.
Thats a very interesting argument. I havent thought it fully through but will attempt to now. The burden of proof in our criminal system is beyond a reasonable doubt. However, in our civil system, the burden of proof is preponderance of the evidence, which means more likely than not. I assume you would agree civil penalties are less severe than criminal penalties (money v jail). Assuming that, then i would also assume that any punishment a college could hand out (suspension from play) is likely less severe than a civil judgment for money damages (in most cases). Thus, thinking this through while I write, my conclusion is that any punishment from a college should not be contingent on a criminal conviction where jail time is a possibility, so my answer to your question is unequivocally no.
What is difficult to decipher still is how should a school adjudicate such an offense? My gut reaction is that it should be done after a full investigation in front of a disciplinary board (which i believe is how these matters are handled and leaves room for corruption as the college is the both the prosecutor and adjudicator), admittedly not a specialty of a college. This should not be done haphazardly. I think a preponderance of the evidence burden of proof should be used (because what is at stake is playing a sport and not jailtime, as explained above). Therefore, unless there is compelling evidence immediately available (eg video evidence showing the student was visibly intoxicated or a failed breathalyzer), i tend to agree the student should be able to play, while the investigation continues. However, since with dwi arrests, there typically is a breathalyzer, then i feel the issue could be resolved rather easily. (If the student refused a breathalyzer, then i think a suspension is warranted until the matter can be fully adjudicated). I would be interested in more facts here, which the university should be able to obtain rather easily.
In conclusion, your premise that a criminal conviction is warranted before a suspension from play is illogical. I think your position is an uneducated one, similar to those who say more guns would solve our mass shooting problem. Overall, like most of us, myself included, i think you should read more and say less. Moreover, we, as a country, need to do more to let everyone know that drinking and driving is a terribly irresponsible thing to do. Greater punishment would help.