MS - your lo should be on 1 nap so I would do my absolute best to ignore those tired signs and to keep him awake until 12pm. He should go down for a longer nap (1.5-2hrs) and then you do bedtime about 5-5.5hrs later.
I think he is using the bottle as a prop to get back to sleep. At 19months he should be able to go all night (11hr stretch) without a feed. What time does he start the day??? 8.30pm also sounds like a late bedtime. If he wakes at 7am, his day should look something like this:
7am - wake for the day
12.30 (the latest) - nap
2.30pm - wake from nap
7.30 (in bed) - bedtime
Try to take him out of the house in the morning, provide lots of stimulation.... get him to run around at the park, etc... and as you come closer to midday, have lunch (say 11ish to allow for bowel movements) and then do a long wind down routine to get him nice and sleepy..... in about a week his body clock should adjust accordingly.
If he continues to wake in the morning for that bottle, I would try wi/wo to get him back to sleep until the desired wake up time. If he's up early and is just chatting to himself then leave him until the desired wake up time. Early morning wake ups are also from incorrect schedule and too late of bedtime.
Here's the link to sleep traning methods....
https://babywhispererforums.com/index.php?topic=63896.0Layla