The best way is to check on your adsense account itself.
All you have to do is:
Log in to your adsense account.
Click on the performance report tab.
On the right, choose the "site" option
This shows page views for the month per each site you own and on which adsense ads are shown. Look for your hubpages subdomain there and see the pageviews, clicks (if any) and and earnings.
If your ads are showing and people are visiting your hubs, you should see page views for your hubpages subdomain.
You can also view page views and earnings on a daily basis. Simply select the date on the top right corner of the performance report page.
Hope I have been able to help you.