I have found it easy - but germination is long in coming - by the time it's poking through - I've forgotten I planted it! About 6-8 weeks.

Keep it watered - it'll come through eventually...

This was a plant purchased from the nursery, not germinating.

I found that when parsley is planted in a pot the pot must be deep since parsley has a long tap-root..... it just seems to do better when it has "leg room".
Even if it's planted in the ground it still needs deep root-room.

Disturbing the roots and changing the pot at this late date (for the plant) may cause it to bolt or flower. Parsley dies after flowering.

FataMorgana

Zone 9 and June may be the issue.

Some zone 9ers may have cool summers but mild winters but if you have 85F / 30C + type weather I would guess that it is too warm for the parsley to thrive. My Parsley grows much faster when temps are below 70F then when it is above 80F, you also said it was in full sun. Have you ever grown parsley in the fall or winter in part sun in your climate ?

Because of the taproot, I've found that single parsley plants bought young do much better than clumps or aged plants. Unfortunately, the latter are more common in nurseries.

It does take a long time to germinate! I let some parsley plants go to seed last fall, and the dropped seeds just started sprouting about a week ago.

I grow Italian parsley all summer long with my tomatoes and it has thrived even in the summer Sacramento heat. This spring may have been a little too cool and rainy for it to grow well until now. I always grow from plants too, I tried germinating seeds with little success. Just give it a little more time now that the weather is warmer.

I plant mine from seed in the winter and it does really well. I soak the seeds overnight.
Mine have done so well I had volunteers coming up in the gravel!

My parsley is bolting, even in the shade. It's too hot right now.

Last summer's parsley in my garden is bolting now too. It's not the heat for me, it's just that time for the parsley.

I direct sow parsley in my garden every year, about the time I think it must have been dud seed, there is it sprouting. I think the key to direct sowing parsley is to forget that it takes so long to germinate and plan to put something else in the spot and low-and-behold, there it is! ;)

FataMorgana

It's getting too hot in your zone. Mine died down a few weeks ago.

In my experience parsley does fine for me in mostly full sun, with a few hours of shade a day. It self-seeds, and before I redid my raised beds this year I had lots of little volunteers sprouting up. I make sure to leave at least one or two plants to overwinter and go to seed the following year.