Too much crate time for 9mo old?

Have a 9mo puggle that came from the shelter. No breeder, no long storied history with this dog. Adopted her this month.

We are trying to get her to understand the crate is a calm place. It has all her chewy toys in it and actual chews. It's comfy inside. Etc etc.

She will bark and whine, then stop and lie down if ignored. Her eyes stay open for a while or snap open at random little things, but eventually she closes her eyes and sometimes does her big sigh of sleep.

I only crate her when I know she has had exercise / mental stimulation needs met. I also check if she needs water always, because this cute little fool just doesn't go for it unless I'm near it or something.

I am worried I am putting her in the crate for too long. Sometimes I wait for her to quiet down, then let her out for a break. I have her in there quite a bit because I don't trust her yet. But that doesn't mean she's unsupervised – she is Always supervised.

How long is too long? I don't recall if we have ever had her in there longer than 2 hours at one time (sounds like a way long time) before going out or playing tug, except of course for sleepytime.

I appreciate feedback. I don't want to turn this into a negative scar for her. We already messed it up the first couple nights and have had to work back up from there.