I have a 1098 — student loan interest — for $889 . Is this not fully deductible? My refund does not reflect this. My income was barely $10k ...

The easiest way to see if your received this deduction is to check your forms. Here's how to look at your current year return forms:

• In the left-hand menu bar, click on Tax Tools, then click Tools.
• Under Other helpful links, click View Tax Summary.
• Your Tax Summary will be displayed. In the left-hand menu bar, you will see a new option: Preview My 1040. Click it, and this will allow you to see the forms.

This deduction will be on Line 20 of Schedule 1. 

if you only had income of $10,000, there was no tax to pay.  I suspect all your withholdings were returned.   the loan interest didn't change the amount of your refund (i.e. you can't get a refund more than what was withheld)