Right now, 88.3% of miners have signaled support for SegWit2x. It does not look like the Bitcoin blockchain is going to split. Which is great for the stability of the overall cryptospace, in my opinion.
I think it is prudent for such a large exchange to make sure that they have made their position clear prior to the activation date. This signal of a lack of support for the chain split by coinbase could help to solidify support of the consensus.