It's possible that he's hitting hormones early, but they normally hit it at 1-3 years of age. If he's DNA sexes as male then he should be humping you or his toys if that's the case. Birds don't often use missionary position to mate, though I do recall there is one species that will on occasion. Avery will crawl into my hair and go crazy and play with it - she absolutely adores being in it, haha. Also, if he saw you as a mate, his bobbing should result in regurgitation. Do you notice him ever trying to "feed" you after bobbing?
As for the sounds... that does remind me of mating behaviour, though I've only experienced a hormonal female who crawled into my neck, made cooing sounds, and rubbed herself against me. Basically any time your bird tries this, try it distract them with a toy, a trick, or gently remove them and place them elsewhere for awhile to cool down. It can be very frustrating for a bird to see you as a mate because they may become sexually dissatisfied, so lots of "cool down" time may be needed. Also, try to avoid petting provocative areas such as the back, shoulders, under the wings, and near the cloaca. Neck and above should be safe, but gauge it based on your parrot.
As for the misbehaviour... anything can cause that. Molting can definitely make them moody. Not wanting to do tricks that day, or just simply having no motivation or desire to do what you're asking could also just be the result of an off day.
Here's some great websites for help regarding what to do with a hormonal bird (if that's the case):
http://www.beautyofbirds.com/sexualbehaviorinbirds.html
http://www.parrotplace.ca/hormonal_parrot.htm
When conures first hit hormones, it varies from bird to bird, where you're located, and what kind of light your bird is being provided with. I think the general rule of thumb for first time hormones Is about a year of "nasty" behaviour at the worst... but I'm not sure. Generally their breeding behaviour starts in February (from what I recall - don't quote me), but I'm quite positive that they can also choose to breed more than once in the year (once again, don't quote me on this). I'm personally not positive how long they should be hormonal, but I'm sure a more experienced member will know
