Oopah - that's a weird one.
OK - here's my take: I assumed in the earlier post that the student was 1st going onto BB. At which point I would've said: "Turn down any 'conditional' belt and state - in no uncertain terms - that if he's good enough for a 'conditional' belt; he's good enough for the real thing."
BUT the student's a 2nd.; and that complicates matters - skill and time or not; I don't know how well a second jumping to Shodan would go over within the local community.
At this time; I really need to know exactly how long the student has been doing aikido; with what frequency; what his focus in the art is and exactly why - besides time in - he feels he should be a Shodan.
All that being said; I'd really like to know what the Sensei's idea is as well - making a 'conditional' yudansha must be one helluva lot more complicated than just promoting a deserving candidate; for all the awkward questions the student has to answer; he's gonna have to answer a lot more.