I have no doubt that a 9.3x62 will settle a lion's hash. The question is, how quickly?
IMO, a frangible bullet (i.e., a CoreLokt or Partition at 2,500+) would be a good choice.
Cats are susceptible to shock. A bit more velocity with a "soft" bullet is more prone to success on a first shot.
In a 9.3x62, a 250 grain cup and core might give you a better result on a first shot than a 286 at 200 fps less.
My personal experience, it should be known, is limited to one lion. It was well hit, but a 400 grain A-Frame out of a .416 Rigby showed no immediate effect. MV was 2,262 fps and the bullet just zipped through. The followup, in the dark, was shall we say, exciting. I don't care to do it again.
If I were to shoot another, I would opt for a .375 with a 270 grain Partition or CoreLokt (or something similar).
For the followup, a well fitted, fast handling double. Definitely.
