9 is pretty easy with new cloth. The pattern is very well known, and is part of the artistic pool competition. I think at the end of the shot, the cue ball has to end on a dollar bill.
On carom tables (10-foot), 9 cushions is fairly easy even with old cloth and rails. On a carom table with new cloth, I was trying the standard 11-cushion shot. That's like the 9-cushion, but the 8th-9th rails are "natural" or "running" because the cue ball goes so long off the 7th rail. Mike Massey happened to be in the room, and he made the shot on his third try without looking like he was really trying. At the recent 3-cushion challenge-shot competition in Las Vegas, Mike was practicing his "M-M" shot, in which he hits 10 cushions in a very strange order to draw an "M" on the table before the final two balls. He made the shot on 11 cushions once. Here are the rails -- I don't have the Wei table handy:
Stand at the foot of the table to watch. The cue ball starts in the lower-right corner. Then: middle of left side, head rail, right rail, left rail near middle, right rail near foot rail, foot rail, left rail near middle, head rail near right end, right rail, left rail about 1/3 away from your end, balls. That's 10. He also made it by hitting the foot rail and then the balls for 11 rails.
I think that 12 on a normal table is impossible without a masse shot. Sayginer has a 12-cushion masse shot on one of his videos. If someone claimed to be able to get 12 without some kind of trick or masse, I think they could get a lot of bets.
The 9-cushion shot is fairly easy on a 6x12 snooker table depending on the cloth and rails. The table where I play has the standard fuzzy snooker cloth and good cushions. On humid days you can stand at one end and send the cue ball straight up and down the table and hit the rail you are standing by three times. There is a report of a trick table on which you could hit the far rail 5 times -- on many pool tables, it is hard to hit the far rail 3 times.