I'm not familiar with Cali junipers (being in the UK), but for any of my junipers (sabina, regular chinesnis, itoigawa and shimpaku) I'd really want to see lots of nice extension growth before even thinking about repotting it (i've lost more than one juniper through repotting).
I'd feed it and give it all of next year to really bulk up, it needs to be vigorous and healthy before rootwork and it's the foliage that really drives juniper root growth.