Re: 8 1/2 month old has never stn weight loss and sleep...
Depends on whether or not the decline in percentile was related to his good intake, or just a normal aspect of his development! If he really hasn't been eating enough, then I'm sure things will pick up as he becomes more interested in solids. But it's quite possible that the decline in percentiles was totally normal. In the second half of the first year, many babies drop on the charts, as they become increasingly mobile and start putting more calories into reaching/rolling/crawling/kicking/standing/etc., and packing fewer on as fat.
1) do you think that he will catch up with his weight eventually when he finally gets used to me being away for part of the day.
No, I really don't think sleep training is a good idea unless you are willing to feed your baby predominantly on formula. Your baby isn't eating during the day, and that means he's probably getting most of his calories, and doing most of the work of maintaining your milk supply, at night. This sort of reverse cycling is common in babies whose moms work. In addition, you say you have no time to pump at work. No pumping during the day and no nursing at night will likely result in no milk in fairly short order.
2) and do you think i might be able to gently sleep train him. having to work full time in various shifts that range from 6am starts to finishing at 11pm within in 1 week. tbh i am amazed that i still have milk as with my other 2 girls i dryed up. although that were sleeping through the night by the time i returned at six months.
No, there are mellow boys and not-so-mellow ones, just like with girls. I don't see how the timing of your return to work could have affected anything, either. Babies don't really want their moms to leave them, no matter if the baby is 3 hours old or 3 months old or 3 years old!
3)also so you think that he is fretting even more because he is a boy AND because i didn't go back to work when he turned 8 months?
Coolest thing my big girl said recently: "How can you tell the world is moving when you are standing on it?"
Coolest thing my little girl sang recently: "I love dat one-two pupples!"