Section 3. A disclaimer shall be executed and filed pursuant to the provisions of this chapter at any time after the creation of the interest in property being disclaimed, but in any event not later than nine months after the event determining that the beneficiary is finally ascertained as the beneficiary of such interest and that such interest is indefeasibly vested and in the case of a beneficiary who is a surviving joint tenant or tenant by the entirety, a disclaimer shall be executed and filed in any event not later than nine months after the death of the other joint tenant or tenants or tenant by the entirety; provided, that any court having jurisdiction of the property, an interest in which is being disclaimed, may, upon petition filed by the beneficiary, the duly appointed guardian or conservator of a beneficiary under a legal disability, or the legal representative of a deceased beneficiary’s estate, permit an extension of time to execute and file a disclaimer, for such further period of time as the court in its discretion deems advisable.