The BEST thing is to ask your Pediatrician. Each Pediatrician may have different recommendations.
For us, our Pediatrician suggested these types of "puffs" or Cherrios at 12 months old. This is per safety & choking, the child's ability to "swallow" and "chew" etc. which is not yet fully developed.
Also, this type of finger foods, ie: the puffs, are given not necessarily as a "snack" per say, but also as a way to let them practice fine motor skills (ie: their finger pincher-grasp) etc.
Keep in mind, that for the 1st year of life, a baby's PRIMARY source of nutrition is breastmilk/formula... NOT solids. You need to nurse a baby BEFORE giving solids...otherwise they will be too full to nurse after solids.
It does not necessarily matter how many teeth a baby has... it is their ability to swallow/mash/chew/and move the food from the front of their mouth and then swallow. Some babies still have their "gag reflex" and/or are still pushing food out of their mouth with their tongue.
If I were you, I would first ask your Pediatrician. Then ask her/him about "snacks."
At this age, it is not crucial that they have "snacks" as it would be for toddlers. At this age of 8 months old, they are still just getting used to eating solids... and nursing/formula should STILL constitute the primary "meal."
No matter what, even at 2 or 3 years old... you must ALWAYS supervise and monitor their eating and helping them, due to safety and choking. Even a young child can choke on tidbits of food. Also, babies and young children don't always "know" how much food to put in their mouths, and they often put too much in their mouth... thereby causing a choking hazard.
All the best, sorry for rambling,
Susan