Trying to get S Rank

That doesn't even make sense. You're either adc or support, you can't be both.

I suspect you're suggesting queue as support, and play the adc role in order to try to get graded as a support, but the system doesn't care what champ select role you got and just looks at your gameplay. If you adc, then you'll be graded as such, and if you support, then you'll be graded as support.

As for the OPs issue...blue trinket is an odd choice for a support. Unless you've been exceptional vigilant with pinks, you wards cleared stat is probably pretty low compared to other sion supports, which might be one of the factors holding you back.