Anyone who has applied for caste Validity? Need ur help

So basically I hv applied for caste validity but the cert will take months to come.. will cap registration allow the receipt? And how long do I have till I have to submit the actual certificate?

Also if I get selected in a college with obc caste in list 1, but still don't have the cert.. what happens next.. which list will I apply on next? How does that work.. plz help