ExpoDev for iOS does not require Plotter to be installed anywhere as long as you still have your exported film files (the same files that you synced to your Palm device). ExpoDev for iOS still needs exported film test data in order to function. These are the same files that the Palm version needed so if you have those already, there is no reason to run the Plotter again. These small exported film data files have an extension of ".xdf". You transfer them to you iOS device using either iTunes or by simply emailing them to yourself and then opening the email attachments on the device (once ExpoDev is installed). There is no other syncing program required for ExpoDev on iOS and it is much, much easier to transfer data files now.
If you don't have those .xdf files that were exported from your Plotter film tests then you may need to run the Plotter again to export them or if you had your film test analyze by Fred at the View Camera Store, contact him to get a copy. There is no way to get these back out of a Palm device unfortunately.
If you do need/want to run the Plotter on your Mac then you will have to either use Bootcamp or one of the various virtualization packages (Parallels, VMWare, etc...). If you do go this route any version of Windows from XP to Windows 8 will run Plotter but I would suggest going with Windows 7 if you can.