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.