Just got this juniper and the foliage is dense up top. Wondering if it’s ok to prune some of it to get more sun in the center of the tree? Also the soil does not look like the best bonsai soil. Should I wait to report it in better soil, if so when can I repot?
Definitely wait until a better time to repot provided you can manage watering in the meantime. Simple risk V gain. Repot now is
definitely risky. Leaving in poor soil
may be risky. Try to manage care to suit the current soil. Only attempt out of season repot if you feel the gain outweighs the extra risk.
Many growers are now repotting successfully in late summer when growth slows but still enough time for roots to recover before cold winter. Spring is the traditional tried and true time for repot. Hopefully you will get some input from experienced growers from similar climate zones with more than just theoretical advice on repotting.
The design is definitely odd! You can prune a bit at any time but also consider wiring as a means to get light into the tree. Pruning and wiring together is probably the best option.
Be aware that rough handling in spring and early summer can kill sections of juniper so if you wire do so gently and bend carefully. Might even be safer to wait until after mid summer for any wiring and bending.