Rob
Ansys Employee

The various nonNewtonian models were created to cope with the wide range of viscous behaviour. So, pick the one that best matches the data you have. Hence, there's a Carreau-Yasuda example on the Customer Portal (students don't have access) as it's good for blood and not in the core Fluent solver. 

If you're using Fluent do the post-processing there. Not sure why wall shear is/isn't available but it's likely linked to model settings and what's included in the data files.