Yes! You can access your Hushed account on multiple different devices…and even at the same time (tablets included)!
Keep in mind, if you’re making or receiving a call on multiple devices logged into the same account, only one device can be used at a time for calling.
NOTE: For security purposes, Hushed Messenger encrypted messages must also be sent/received from a single device that has been set as your default device. See "What is a Hushed Messenger Default Device?"