So far I've seen a confirmation from Coinbase that they will credit BTC holders with an equal amount on the new blockchain. I'm assuming that other exchanges will follow suit.
The question is, will you stack BTC up in preparation?
Yes, some exchanges will credit 2x to BTC holders. But my opinion is that it's always risky to put money on exchanges for a long period of time. They could be hacked or scam people and then disappear. It's safer to control your private keys on a light wallet like electrum.
Then, when the storm will be over, you can take all the time you want to claim your new 2x coin on a new wallet (like many of us did for BCH). When 2x will be listed on exchanges you may trade it for BTC or just keep it in your wallet and hold for the long term.