It looks like 274afad introduced an issue with CommonJS imports. @react-spring/shared does not currently have a rollup config that would output .cjs.js files, yet these are now being referenced as a result of that change.
I've added a comment to the beta feedback issue already.
Steps to reproduce the behavior:
Install v9.0.0-beta.28 and use a commonjs entrypoint. This will then complain about being unable to resolve @react-spring/shared/global.cjs.js as this file does not exist.