It's not wasting time if after sponsorship and son's 2nd landing, the OP becomes Canadian citizen and lives with the son outside Canada until he is ready. Note that minor child accompanying a Canadian citizen parent preserves PR status.
This is true but even better, if the OP applies for citizenship and the son is PR at that time, then the son can get citizenship on the same application.
However, if the OP is not considering applying for citizenship at this point and the son is living with someone else in another country and likely to continue doing that in the future, then the sponsorship could also wait until the son is a bit more grown and can decide where he wants to live.