Using AC connectors with DC voltage
You have three things to consider, and these are not necessarily in order of importance

a) whether it 'works' electrically
b) insurance and liability issues
c) servicing by other people

a) 90v is higher than the generally recognised 'safe touch' voltage of around 40v. As long as the connector is adequately insulated for the voltage, and conductors sized for the current, that should be OK. 

b) Is this a one-off for your own use, or something you're selling? Either way, if it fails bad and causes damage, will the 'off rating' use (misuse) of this connector void any insurance that's covering your property, or lives of nearest and dearest? That's what UL ratings are on components for, when used within their ratings, they are deemed to be OK. Use outside their ratings, even if it looks OK for the purpose, then all insurance bets are off. It is insurance companies' main job to wriggle out of liability on the slightest pretext they can find. An off rating connector in the thing that started the fire, even if it wasn't the component that started the fire, is just what they're looking for.

c) The components used tell a story to a somebody opening up the equipment to mend it, or learn from it. Will the connector mislead, and cause a hazard, because of its 'off rating' use? You may think it's OK to use a mains connector to connect some low voltage circuits together, but what happens if somebody else sees a mains connector, and connects it to mains? Don't embed hazardous surprises for someone else to find.