is it allowed to say “I need to obtain only one more year of work experience before I will receive the CFA charter”? (assuming it is a factual statement)

No, It is a violation if one says, “I anticipate my Charter in x months/years”

Try fitting that on your business card…

I have this punch line on my Business Card already - “I pissed my pants 3 times per session ever season of CFA exam taken and I am still at L2 … more wettings on the way”