Q1: Does the digivolution requirement that this card digivolve from a Tamer mean the Tamer that becomes a digivolution card is treated as if it is a Digimon when digivolving?

No. Digivolve from the Tamer as such, and do not treat it as if it is a digivolving Digimon. "When digivolving" effects and "when a Digimon digivolves" effects don't trigger. Additionally, if a "Digimon can't digivolve" effect has activated, you can still digivolve from a Tamer with this digivolve requirement.

Q2: Do I perform a digivolution bonus draw even if I digivolve from a Tamer?

Yes, you do. A digivolution bonus draw is performed for any kind of digivolution.

Q3: If this card digivolves from a Tamer that was played this turn, can it attack this turn?

No, it can't. A card cannot attack on the turn it is played, even if it digivolves from a card placed on the field. It can only attack if it was not played that turn.

Q4: Is a Tamer card placed under a Digimon considered a digivolution card?

Yes, it is. If the Digimon leaves the field, that Tamer is trashed like normal digivolution cards.

Q5: Does a Digimon gain the security effects in the lower text of a Tamer card in its digivolution cards?

No, it does not.

Q6: Does a Digimon gain the inherited effects in the lower text of a Tamer card in its digivolution cards?

Yes, it does.