By using the migrate function, you bypassed the installer's requirements check. CS4 is looking for an HFS+ drive and isn't finding one. You'd get an error message if it were formatted as case sensitive, too.
You could make a separate partition and format it HFS+ (Mac OS Extended). High Sierra does still allow installation and booting on an HFS+ drive, but I presume the new Mac is using an SSD. In which case, it may reformat the drive as APFS whether you like it or not.
Another option is get Paralells Light from the App Store. That is free and allows you to install virtual machine Mac OS drives for no cost. So, you could take an older OS you acquired from the App Store, such as Yosemite, and install it on a Mac OS Extended virtual drive with CS4 running in that.