The Dotdotdot Vault 9.7 score is based on a variety of factors, including the contract's immutability, multi-signature capabilities, and other security measures. Immutability is important because it ensures that the code of the contract cannot be changed without the consent of all parties involved. Multi-signature capabilities are also important because they make it harder for malicious actors to access the funds in the vault. Additionally, the vault's security measures are evaluated to ensure that the funds are safe from external threats. Finally, the vault's customer support is also evaluated to ensure that customers can get help in a timely manner. All these factors are taken into account when Dotdotdot assigns a safety score to the vault.