if a leblanc token is already created but an enemy uses something to bounce the original unit to hand and starspring battlefield is empty does the unit get temporary.

Yes — the Reflection token still gains Temporary even if the copy fails.

The Deceiver reflexive trigger is a single instruction set: "It becomes a copy of another unit there. Give it [Temporary]." If the intended copy target is bounced to hand (e.g., via Star-Crossed) and Star Spring is empty, the copy part has nothing to operate on and is ignored, but the Temporary grant is independent and still resolves. The token remains a 0 [M] Reflection (not a copy) with Temporary, and it will be Killed at the start of your next Beginning phase per the Temporary trigger. This matches FAQ #11492 — Temporary comes only from the granting effect, and a failed copy doesn't cancel it.