Is there a reason you need to turn the breaker on for that circuit? Is it connected to a circuit like your kitchen or something?
In my opinion, if you aren’t an electrician and can leave that circuit off until your friend or whoever can look at it, then just leave that circuit off. That is the safest approach.
Otherwise,so long as the wires are not touching and the black and blue wires are capped off and not touching bare metal, in theory you should be okay. Again, this is theoretical, it is possible that there may be something that I cannot see or think of that may cause a house fire by turning that circuit back on.