@Arne *******
First, if you want to get 9 months out of your visa, you need to enter as soon as you get it. Do the calculations yourself:
- METV is valid for 6 months, need to enter and re-enter within those 6 months
- 60 days per entry with possibility to extend another 30 days
I'd say you probably won't be able to get 9 months out of your METV (you would be able to get two visa-exemption stamps per calendar year by land, though).
Second, if your girlfriend still hasn't gotten her visa, the time used up to get her visa is eating away at the time of your METV.
Third, if your girlfriend gets her visa a few weeks after yours, the timing of your border runs will be different. You will have to do your border runs separately, or one of you will have to lose a few weeks from the total time of their visa.
Fourth, another option is to get a SETV, which gives you 60 days, and the possibility to extend for another 30 days for 1,900เธฟ at immigration. You can wait before entering, because there are no re-entries. Then, you are allowed 2 visa-exemption stamps per calendar year by land, which since October 1st gives you 45 days, and the possibility to extend for another 30 days.
I've given you all the information you need, to do the math according to your travel plans.