You can use npx command which is Node.js package runner, by running packages directly from the registry without effecting the globally installed package registry (-g).
@next will automatically install the latest preview version from Angular repo (now days refers to version 9 rc), like so:
npx @angular/cli@next new Angular9Project
Otherwise, you can provide the specific version:
npx @angular/cli@7 new Angular7Project
NPX comes bundled with NPM version 5.2+