Am I allowed to open at the "one" level with hand like AKQxxxx xx xx xx?
The ACBL Convention Charts are a list of allowed agreements in the ACBL (but not necessarily other organizations).  You would need to determine which convention chart was being used by the particular competition you were involved in.
Let's check a few.  Please note the following applies to 1H and 1S and not to the minors, which have different rules related to them (though in this case, likely the same - just being clear it's slightly different spots in the rules.)

On the Basic chart, the rule that would control what you may mean by &quot;1 Spade&quot;, is the following:

Opening Bids


Any Natural opening bid in a suit, as long as it shows at least Average Strength.



Further, let's define terms:

(1c). “Average Strength”: A hand that has at least 10 HCP or meets the “Rule of 19”.
(17). “High Card Points (HCP)”: The total number of points in a hand based on honors,
counting 4 for an Ace, 3 for a King, 2 for a Queen, and 1 for a Jack.
(27). *** “Rule of N”: A method of determining hand strength computed by adding the High
Card Points of the hand to the number of cards in the two longest suits. To meet the
“Rule of N”, this total must be at least N. *

There is no relationship to the Weak Two range here; what is specifically controlled is whether the &quot;1 Spade&quot; bid is considered permissible.
So we must evaluate your holding here, and see if it fits the range for &quot;Average Hand&quot;.

HCP: It has 9 high card points, and does not meet this standard.
Rule of 19:  The distribution is 7-2-2-2, and with 9 HCP, it is evaluated at 9+7+2 = 18.  Thus, it does not meet this standard.

Thus, it is not permissible under the ACBL Basic Convention Chart to have an agreement to open this hand 1S, as a natural bid.

On the Basic+ chart, the rule is:

Opening Bids


Any opening bid in a suit which is Natural, as long as it shows at least Near-Average
Strength.



Defining Near-Average strength:

(1b) “Near Average Strength”: A hand that has at least 8 HCP or meets the “Rule of
17”

This hand is &quot;Near Average Strength&quot;, both because it has 9 HCP and 18 &quot;Rule of N&quot; points.  This would be allowed on Basic+ to be opened 1s.

On the Open chart, the following rule applies as to what is disallowed - Open allows all agreements other than what is disallowed.


*** A Natural or Quasi-Natural 1-level opening bid in any seat that could contain less than Near-Average Strength.


This hand is Near-Average Strength, as previously discussed, and so is permitted.
Open+ is more permissive than Open, and so also permits this hand to be opened 1s.

In summary, here are the options:




Chart
1S permitted?




Basic
No


Basic+
Yes


Open
Yes


Open+
Yes