I used to do it a couple of years ago and if I left at 7am I would be at the IFSC at 8.20am. It gets really bad around Lucan at Woodies and the Quays are always busy. The train might be easier as you could get a dart to Landsdowne Rd.
Train service is not too bad, there are 2 trains at peak time in the morning from Kilcock( 7.27am and 8.08am) and evening from town(17.15 and 18.05). Journey time is about 45-50min depending which station in town you are going to.
Alot of people drive to Maynooth station which gives a lot more options although the car park fills up pretty early.