I run 235/75R15's on my '87. The tires would rub on the sway bar (if the sway bar was installed) and, occasionally it hits the passenger fender if everything is just right. Technical data I have for Cooper tires suggests that a 30x9.5 is less than 0.5 in taller, so I wouldn't be surprised if it fits acceptably.
BTW, I've put the 31x10.5R15's from my Explorer onto my BII, and they are driveable, but they rub quite a bit if the suspension flexes or when turning sharp.