Parents and Me and Baby Seperation Anxiety- What to DO?

My nanny kid is a recently-turned-1yr old boy: VB. I am his full time nanny, and his most present caregiver. I honestly spend more time with VB than both of his parents ever actually do. Not to say that they don't care about their son, I am simply saying that they aren't exactly as "clued in" with this kid as well as I am, because I am the one caregiver who spends the most time with VB.

I am everything short of an actual live-in nanny for this family. Which is fine. The pay is good. The family is great. The parents and their 3 older kids all love me and respect me. I am very happy here. I just spend a lot of time at the house with VB specifically, and am just now learning his body language, now that's he's walking and is more mobile. He's not talking yet tho. Just normal squeals and laughs and "Dadada," and, "Tatata" and "Guh."

My main concern is for 1yr old VB. This is my first Full-time Nanny position and I've been working for them for the past 8 months, starting when VB was 4 months old. VB knows me as his caregiver/friend/buddy. He knows his parents are his parents and I am simply his caregiver. VB is very aware that I'm not home 24/7.

All this to say that VB has shown signs of seperation anxiety since he was maybe around 8-9 months and it has only worsened since then. He's a walking 1yr old now and I'm worried about it. I'm not worried about the seperation anxiety itself, but more so his reactions to it. This baby screams and rages, and he'll follow you around, begging to be picked up, escalating to the point of hysterical tears and red face and snot if not picked up quick enough. Even distracting him when parents leave with proper play and talk and songs aren't enough at times.

This behaviour has always been exhibited strictly with his parents, whom come and go from the house as they please. Mom works from home, and Dad likes to go in and out of his work office. It's kind of like a revolving door in their household. You simply never know exactly know who's gonna stop by at the house on any given moment throughout my 9 hour work days. But that also means Mom and Dad both leave or stay whenever they want, and get their work done.
So, VB has many potential opportunities for his seperarion anxiety to show itself. He whines for either of his parents as soon one of then steps into the room or when he hears their voices.

For the very first time this week, VB suddenly and unexpectedly started showing extreme signs of seperation anxiety when I left for the day, which again, is something he knows that I do. He knows I leave the house and that I won't see him for another 12 or so hours till my shift starts again the next day Mon-Fri.

It alarmed me when he did this the first time. And I just don't know what to do to make the seperation anxiety better for him. I don't want him screaming like this for another year. It tugs on every ones heartstrings. I just hate the way VB gets SO very upset, almost inconsolable at times throughout the week. Does any one have any advice for me. I don't know if I need to make some sort of strategy with the parents for it? They haven't said anything they might want me to do for him. I have told them that I've researched it and implemented the things I learned with VB. But even still, the things I am doing aren't working long term, especially now that he's learned to walk and can "chase" people. I'm at a loss.
Anyone got any advice?

Thank you!

-Eliza