Yep. He still plays both English and American pool, 8 or 9 ball, with a snooker cue. I guess he has just played so many shots with a snooker cue that it just feels more natural. Steve Davis played pool with a snooker cue at first and then got a special "hybrid" cue made.
I guess most UK snooker pros will have played a little English pool in the pub but English pool cues and snooker cues are pretty transferable (English pool cues have even smaller tips - Gareth Potts once played an English 8 ball tournament with his snooker cue when he was back home from playing Chinese 8 ball as he had got so used to using the bigger tip).
The top snooker players are such good cuesmiths that I'd rate them as favourites with their snooker cue over anyone but a pro level pool player. Steve Davis was asked why he didn't use a pool cue and said something like, "I'm a snooker player, I love 9 ball but I never practice". He was still good enough to do well as a wildcard in the 9 ball world championships he played in. However, if he made a move to pool, or if Jimmy played pool regularly beyond the exhibition matches, I'm certain they would practice and play with a pool cue in order to up their game.