The NRSV-CE (1989) comes from the RSV-CE (1966), which is a 1946 Protestant translation with all canonical books included (pp. xviii & 9 of Which Bible Should You Read?).
The NRSV-CE omits "fasting" in its translation of Mk. 9:29 (so does the NABRE):
He said to them, “This kind can only come out through prayer.”
cf. Rheims's Mk. 9:28:
And he said to them: This kind can go out by nothing, but by prayer and fasting.
Fasting scandalizes "modern man," so it's left out.
Which Bible Should You Read? pp. 28-30 gives another example of a glaring omission of verses in nominally Catholic bibles: Ecclesiasticus (Sirach) 24:24-31. The Douay version reads:
...  I am the mother of fair love, and of fear, and of knowledge, and of holy hope.
Ego mater pulchrae dilectionis, et timoris, et agnitionis, et sanctae spei.
...  In me is all grace of the way and of the truth, in me is all hope of life and of virtue.
In me gratia omnis viae et veritatis : in me omnis spes vitae et virtutis.
...  Come over to me, all ye that desire me, and be filled with my fruits.
Transite ad me, omnes qui concupiscitis me, et a generationibus meis implemini :
...  For my spirit is sweet above honey, and my inheritance above honey and the honeycomb.
spiritus enim meus super mel dulcis, et haereditas mea super mel et favum.
...  My memory is unto everlasting generations.
Memoria mea in generatione saeculorum.
...  They that eat me, shall yet hunger: and they that drink me, shall yet thirst.
Qui edunt me, adhuc esurient, et qui bibunt me, adhuc sitient.
...  He that hearkeneth to me, shall not be confounded: and they that work by me, shall not sin.
Qui audit me non confundetur, et qui operantur in me non peccabunt :
...  They that explain me shall have life everlasting.
qui elucidant me, vitam aeternam habebunt.
But the NRSV-CE of Sirach 24 omits the bold verses above, and NRSV-CE v. 19 corresponds to Douay v. 26! Douay vv. 24-25's omission is explained in a footnote of the NSRV-CE, but the NRSV-CE doesn't explain its omission of Douay v. 31 in a footnote!
These verses were probably omitted because the Catholic Church uses them in the liturgy for various feasts of the Blessed Virgin Mother, and mention of her is a scandal to Protestants.
According to Which Bible Should You Read? p. 29,
All together, Chapter 24 of Ecclesiasticus (Sirach) has some […] 13 fewer verses in the CRSV [Catholic Revised Standard Version] than the Vulgate and DRB [Douay-Rheims Bible]!
Indeed, the Douay version has 47 verses, and the NRSV-CE has only 34.
The "old Latin vulgate" is the only official edition of Holy Scriptures for the universal Church, as defined in the Council of Trent.