I don't know your climate, so I can't say of it's too late to sow this spring, but the seed will certainly keep.

Since they don't like heat, it seems that waiting until fall would be the best use of garden space, since they are one of your best winter crops (and they feed the soil.) Right now they'll take up space where you can be planting warm/heat loving plants and getting good production from them.

I planted mine in March last year and they did well. I'm in a much different climate than you though.

A few plants, eaten as greens, will be fine. For seed in Zone 9 it is too late. They die a miserable death in hot weather.

I can grow Favas in the summer in my climate you just need some shade cloth to keep some heat off or an area where they get just morning sun and maybe a little bit of the mid day. but NO evening sun its too hot for them yes. I don't like favas very much so i am not growing them again but i have just sown my Bush beans just a few days ago. i will be showing them when they sprout on my youtube channel TheItalian Garden. i will be doing losts of general info videos on there if you would like to tune in would love to answer some question from people who need help.

Here is a link that might be useful: TheItalian Garden