Hi Tonka,
From what you say, with the Word Attack, it sounds like the WJ achievement test (not the aptitude). My DS took this as a kindergartner, and also scored very highly. That particular test isn't especially telling for achievement, IIRC, because it only asks a few questions per category. Someone with more knowledge of this test will hopefully pipe in. I think when you are very young and a very strong reader, you can get some pretty high scores on that test. Did the school psychologist administer the test? If so, can you have a meeting that includes that person? They should be more familiar with (and thus more impressed) with the results.
I'll preface all of this advice with a caveat that it's just meant as food for thought. Some of this worked for us, and may not work for you or others.
I remember my son's K teacher wasn't very impressed with any tests - some teachers just aren't, they want to get to know the kids themselves. When kids score very high compared to other kids, there is a likelihood that teachers have little to no experience with that type of kid, and so they will not know that they might need to take a different approach.
Our school district also didn't offer GT services until 3rd, but we met with the GT coordinator with IQ test scores and asked for advice. It was helpful for us to get outside testing and a full report. This convinced the GT coordinator that they needed to do differentiation for our DS even before he hit third. Try to get the GT staff person on your side and to help you deal with the school, if you can. The GT person can recommend in-class differentiation, or help you with ideas to send alternate materials in, if you need to. I would emphasize that you want to help as much as you can, and if she has any ideas of what to do so that your DD can get some challenges too.
I would ask if there are other kids with similar scores to your DD. Does your school do MAP testing, by any chance? That is open-ended achievement testing that is very helpful to see what your DD already knows. Some schools have this type of test, but don't offer it for the youngest grades. If your school has it, ask if your DD can take it early so the school will know what you're dealing with.
Ask about pre-testing. If your DD can test out of the units that are being taught and if so, can she have alternate materials. I would start with math, because that's easy for the school to measure. If it turns out she is working at the level of a higher grade, ask if she can go to that class. Reading can be differentiated pretty easily (if the school is willing to try). I don't think the classroom teacher will be as impressed with tests such as the WJ (or IQ tests) that are not the testing she is used to, but when she sees what your DD can do on her own tests - maybe even end of year tests -- then she may see the light.
The handwriting was an issue for our DS. He did not want to learn how to write, and so we looked at kindergarten as a "learn to write" year. That was pretty much our biggest goal. That and learning to "do school" for a full day, but it sounds like your DD already had that school experience. When the GT teacher tested our DS on the MAP and started tutoring him in math, it was an extra bonus. We ended up advocating for DS to skip 1st grade, which turned out to be a great decision, but the handwriting came up again when the math still wasn't enough. (They said he couldn't go to 3rd grade math because he wouldn't be able to keep up with the writing.) We transferred mid-year to a school for HG kids that accepts that writing for our DS will be age-appropriate, and they don't prevent him from learning higher level materials just because he has poor handwriting.
It is great that your DD loves her teacher. Can you visit the classroom sometime and see what's going on? There's a possibility your DD is learning things that you're just not aware of - a lot goes on in the classroom that doesn't make it home. Just a thought.
Sorry, bunch of rambling....
