Forever Black is a trim dye. As such it is permanent. It is applied with a foam applicator of minimum thickness, as such, you need multiple applications to eliminate any streakyness that may happen. Just keep applying and letting dry until it's uniform.
As for your leather I'll just say this:
modern automotive leathers (especially a 2009) are plastic coated. As such, no conditioning is necessary. Any conditioner that you apply will merely sit on the surface. It's not possible for it to "soak into" the leather unless you plastic coating is so deteriorated as to be gone. In that case, you have bigger fish to fry.
All that is necessary for your leather is a thourough scrub with a 1:2 ration of woolite to water followed by a clean water rinse wipedown. This will leave your leather matte and new looking like so (keep in mind this is 6 year old leather now in my '06 Fusion so yours will look better than this even)
And the rinse water bucket (formerly clean)