Are you able to write a review about a person if they straight up stood you up, after setting an appointment with you and a specific time but then when it came down to the time to meet you never could get a hold of them and they never responded back to you? Or do you have to actually meet the person and have a session with them in order to be able to write a review? I think other people should know things like this about certain providers who do this.

No meeting,  no review. If you don’t like the policy, take it up with TER and.

...write a review without meeting the provider. However, if you really want to share your experience with others, you can post in your local board thereabout.

A meeting has to take place to write a review, do as the previous 2 replies said, you can not review a NCNS. However you can post about her on your regional board. If she is a well known well reviewed lady, expect her White Knights to come to her defense. To avoid some of that drama, some folks will say to post about it without naming her and to ask people to PM you if they want the name. Others will say name her or your post is worthless.  

reaching out to her today to see what may have happened? Sometimes it is wise to hold off a day or two while you try to reach the provider to get her side of the story. Sometimes stuff does happen in RL.

It is always good to give someone 48 hours or so to get back to you, before blasting them, in case some emergency really happened. However the OP never said when his meeting was supposed to have taken place.

They could also post under an alias, to avoid some of the backlash if they opt to actually name her.  

Often times my belief is that things happen for a reason.  I leave such things alone. At the end of the day I saved money.
Maybe she knew about LE, maybe she discovered that she had an STD.  

Stuff happens.  Personally, I would only consider posting on a regional board if multiple conditions were met that make it abundantly clear that she blatantly disrespected your time (e.g., you made it clear to her that you were taking a day off or reshuffling your schedule just for her and she acknowledged, etc.).  Otherwise give her the benefit of the doubt whenever feasible.  Use the search function and see if she has a history or if someone has posted about her before.  If she has been around for a while and has a lot of reviews, odds this isn't the first time that she flaked on someone.  That said, I suspect that most of that sort of information will be on the RO board vs. other boards.  The search function is your friend and will help you avoid making the same mistake.  

The search function is only useful if someone "names names"  

There would be no history to search if no one reports the bad behavior.