Isn't the tuition deduction extended and now can be claimed on 2018 returns? However, trying to amend return still states that form 8917 is not available? Is this because of the actual form from IRS not available or TurboTax does not have the system updated to recognize this change?

It will likely be months before the tax forms and the tax software are revised for the tax law changes that just passed at almost the end of December 2019.  First the IRS has to revise its forms and then all the software programmers have to get busy changing the software, then the software has to go through the IRS approval process.  That will not happen fast.

You have three years to amend a tax return, so sit tight on amending 2018 for awhile.