I have the same EP and barlow. I have rarely been able to barlow the 9mm for planetary viewing. the seeing has to be pretty darn good for that. I bought a TV 10.5mm plossl and I can barlow that sometimes as it is better than the GSO 9mm, but still the seeing has to be very good.
my guess is that you just need to wait for good seeing....
the reason I say its not the barlow and EP is that if you use it on a bright DSO you will get a good image even in average to good seeing. but to get detail on planets at that magnification you will need v/good to exeptional seeing
