Nope. Case law is clear that refusing to hear a case is in no way a ruling on the merits nor can it be cited as such in any legal brief.
Kinda, yes it does. It can be cited as precedent (see #2)
SCOTUS refusal to take a case has two implications:
(1) Legally, the highest lower-court decision stands. I.e., if a man is convicted in trial court, the conviction is reversed in appeals court, and SCOTUS denies cert., the appeals court decision stands and the man goes free.
(2) The decision not to grant certiorari is a legal nullity. I.e., it does not rule on the lower court's decision -- it doesn't affirm it, it certainly doesn't reverse it. It merely says that there aren't sufficient grounds to review it again, in the opinion of at least six SCOTUS justices (it only takes four to grant cert.). It therefore is not precedent except insofar as it was before SCOTUS took up the question of granting cert. -- i.e., the ruling of the high state court stands as precedent for that state; the Federal Circuit Court ruling stands as precedent in that circuit -- but neither is applicable as binding precedent (though certainly citeable as supportive precedent) anywhere else than in that state or circuit.