Is it possible for creatures to crew vehicles at instant speed? Also, would the following situation work? The opponent issues an attack with a creature. Would I be able to have a creature crew a vehicle and thus have the vehicle block the opponent's creature?
You can activate the crew ability any time you have priority, like most activated abilities (C.R. 116.1b, 702.121a). Therefore, you can activate it after attackers are declared but before blockers are declared (C.R. 508.2). (Compare this with the equip ability, which you can activate "only as a sorcery" [C.R. 702.6a; review C.R. 307.5].)
EDIT (Jul. 19): Added rule citation.
EDIT (Mar. 12, 2022): Edited to conform to updated text for equip in the meantime.
Is it possible for creatures to crew vehicles at instant speed? Also, would the following situation work? The opponent issues an attack with a creature. Would I be able to have a creature crew a vehicle and thus have the vehicle block the opponent's creature?
Thanks for any responses.
EDIT (Jul. 19): Added rule citation.
EDIT (Mar. 12, 2022): Edited to conform to updated text for equip in the meantime.