Yes, Bet365 is safe to use. The sportsbook provides various levels of firewall and other protections and the sportsbook itself is regulated by each of the state gaming regulations Bet365 is legal in.
bet365 operates an Information Security Management System (ISMS) to protect the confidentiality, integrity and availability of information. bet365's ISMS has been certified in accordance with ISO/IEC 27001:2013, an internationally recognised standard for information security.