Yes, it is possible. When I run your code I get the results I expected (sinewaves on ai0 and ai1). Below is a screenshot of the acquired data. Did you have a separate VI for acquiring the signals for validation?
This thread was quite informative but outdated. I want to know if anything has changed since 2004 with the ability to run multiple tasks on the same device. I have cDAQ-9188 which can supposedly run 7 different generations/acquisitions at the same time. I also have an NI 9264 analog output module. I had hoped to group a few channels together in one task that generates DC, and also create another task that generates waveform data. So far it claims that the device is busy if I try to run more than one task at once, even though tasks do not share channels. Is a single module still only capable of a single sample rate?