I think the numerology practice you're basing your question on is Vedic numerology. The calendar day of birth is reduced to a single digit to determine the psychic chart position and the entire birth date for the destiny position.

My expertise is with traditional Pythagorean numerology. There is no psychic number and the destiny number is calculated from the name.

Perhaps a numerologist who specializes in Vedic numerology can help you choose a name for your child.

With Pythagorean numerology, there is no should be or should not be for a name number (the Pythagorean destiny number).

With Pythagorean numerology, your child's destiny number is the number 8 and your child's life path number (the birth date number) is the number 9. Those two are compatible.

The calendar day of your child's birth is the second life period cycle number, the number 9. That cycle will begin at age 28 and last for 27 years.