The 2nd Amendment, recognizing an individual right to keep and bear arms via the USSC in Heller, has now been ruled to apply to the states, not just the Federal government.
This sets precedent (not controlling outside of the 9th Circuit but still persuasive) that the right should be incorporated against all the states. This provides support that several other District Courts with current cases regarding the 2nd should also treat it as incorporated.
Worst case, one doesn't and it sets the stage for the USSC to rule on the controversy.
The 9th, like the USSC, also implied a standard of review higher than mere "reasonability", when addressed by more "pro-gun" courts that may open the way for them to decide to use "strict scrutiny" as the appropriate method. Again, that could send it to the USSC to make that Strict Scrut. interp. nationwide.
So, immediate effects? Not many. Practical effects? Big as is, and potentially HUGE.