In case someone is having same problem with storybook 9 for angular project.
Include styles setting into builder options for storybook inside angular.json

"storybook": {
    "builder": "@storybook/angular:start-storybook",
    "options": {
        ...
        "styles": ["src/styles/styles.scss"]
    }
}

"build-storybook": {
    "builder": "@storybook/angular:build-storybook",
    "options": {
        ...
        "styles": ["src/styles/styles.scss"]
    }
}