QuoteIBM responded that only Active Reports are supported through Cognos I-Pad app
While this is true you can set up your Cognos environment to be used by any browser, mobile included.
If you can connect to the Cognos server just connect to it using Safari (I haven't tested Safari so I don't know how good it will work) but I have tested connecting to my Cognos servers on various Android tablets and phones without any issues.
The largest concern is formatting the reports to fit the screen of the device you want.
If you want to run an Active Report in something other than the Ipad App then the browser needs to support MHTL - which most Android devices no longer support so you are then looking for third party apps that do support it, of which there are several in the Google Play store - (Again I do not know if there is a third party for the Ipad but honestly if you have an Ipad and want to support Active Reports use the IBM App...)