Is marinade safe if it has had incidental contact with meat?
Not completely clear on what you've done. If you used the spoon just to pour over the chicken, from a few inches or more above, then the spoon wasn't actually contaminated (provided you didn't get splashes of chicken juice on it). If you used it to stir the chicken in the marinade, or to rub the marinade on the chicken, or it otherwise came into contact, then yes its considered contaminated.

Assuming it is contaminated, it is safe provided you treat it as you would chicken: store it in the fridge, not for more than a day or two; cook it thoroughly before consuming; don't let come into contact with other food (or that food will be potentially contaminated as well), etc.

You could also go ahead and cook it now; you can then store it like you would leftovers.

If you need to store it longer, freezing it will keep it safe. Most marinades will handle freezing fine, though you may need to re-mix it upon thawing.

I suggest labeling it—especially if you freeze it—so you don't forget that its potentially contaminated.