We lived there for a while a until 3 years ago and moved back to Dublin as the daily commute was killing us, but as you're already in Naas this may not be an issue. However, bear in mind there is only the shop/pub, Naas is a hopping metropolis compared to Calverstown, which in reality is only a crossroads with a pub at it. Most of the newer houses are owned by Dublin workers so the place is empty during the day.
Can't give a current comment on the slip road off the M9 but it was never a problem for us, but you are turning right onto a fairly busy road now so it may be worse, I'd try it several times.
It does get very cold in the winter in Calverstown, its in a hollow so tends to get a lot of cold still air, and a LOT of fog. Theres no natural gas there so all heating is oil based. And as theres no footpaths to speak off you won't be walking far on dark evenings unless you want to play chicken with cars at 70mph!
It is apparently supposed to be a posh part of Kildare and in summer looks lovely, but everything you do will involve getting into the car.
Hopefully if you decide to move there your experience will be more positive.