It's hard to find a clear answer especially since a lot of news is from before the second announcement on Dec 26th (still looking). Please reply if you have any other info.

I think hardware is the best option but some exchanges may support the fork. This is a list of exchanges from October which might give some minor indication but don't count on it. At first glance, I don't see any that have made a more recent official announcement.
WARNING THIS LIST IS NOT ACCURATE ANYMORE
https://blog.coinigy.com/2017/10/comprehensive-list-of-exchange-segwit2x-stances/

I've seen others recommending Binance and Bittrex because they are generally good at this but I don't see any official announcements.

Other Sources:
SegWit2x has a list of exchanges on the home page, I haven't heard of any of them.
B2X Official Site FAQs: http://b2x-segwit.io/faq/

B2X Futures Trading (probably not recommended​): https://hitbtc.com/?ref_id=59e74ee59e961