No, not for real conditions. Italian uses the indicative for likely/real conditions: Se vuoi, ci sto.
For hypothetical/unreal conditions, you use the imperfect subjunctive + conditional: Se volessi, ci starei (If you wanted, I would be in).
With a conjugated verb, ci comes before: ci sto, ci stavo, ci starò.
With infinitive/gerund/imperative, it attaches: starci, stando(ci), and colloquial imperative stacci! (accept it!). Do not say sto ci.