I would like to transfer music DCs to the iMac and also listen to them there and, if possible, on the iPhone. Is this possible with the ASUS ZenDrive U9M? Can I use this as a replacement for the missing CD drive on the Mac? Or what else can I do?
I have Windows (no Mac) and therefore cannot judge this conclusively, but I see no reason why this should not work, as this device also works with Mac's, e.g. according to the description of this product: "Two cables for data transfer with PC and Mac are included in the scope of delivery".
In addition, software for ripping music CDs is required. I don't know whether Macs (macOS) have something included as standard. Or whether the software that comes with this product supports this and is also compatible for macOS, I no longer know. However, if there is nothing included with macOS or this product, there is various software for it, e.g. foobar2000. According to the main features of foobar2000: "Support for ripping Audio CDs as well as transcoding all supported audio formats." foobar2000 is also available as a download for macOS.