I would use hollow points on lions not hard casts. A lion is not much denser if not less dense than some people. A hard cast is massively overkill and would just be throwing a wad of lead at it. Id rather have something that expands fast and does major damage. Youll maybe get off one shot in a cougar attack so better make it count. When I hike and bike where I know there are lion I take either my 10mm with Hornady JHP's or my .357 with starfire HPs. From a veterinary standpoint I can say your average good HP will be more than enough from either of those hand cannons. Honestly I wouldnt be afraid to use a hot loaded .380 let alone a 9 mil on a cat.
If a man hasn't found something worth dying for, he isn't fit to live