When will digital show?

In people's experience when will a digital clear blue test show a positive result. I started testing 4DPT (9DPO) I got this result this morning being the strongest second line so far 7DPT (12DPO) but a clear blue digital said not pregnant. After 4 and a half years trying and our first <a href="https://glowing.com/glow-fertility-program">IVF</a> cycle I can't accept it fully until I see the word. Opinions please